The Magazine from Carl Zeiss Visual Perception the Fascination of the Eye Diagnosis – Therapy

InnovationThe Magazine from Carl Zeiss ISSN 1431-8040 17

Ⅲ Visual Perception

Ⅲ The Fascination of the Eye

Ⅲ Diagnosis – Therapy – Follow-up Care Contents

Editorial 3

In Focus The Eye 4 The Fascination with Seeing 6 Visual Perception 8 Optical Illusions 12 Human and Animal Eyes 14

Milestones Luxury Article or Basic Commodity? 18 The Early Days at Carl Zeiss 22 A Tradition of Innovation 24 Enhancing Vision with Refractive Surgery 30 The Sensitive Sensor 32 An Insidious Loss of Vision 36 The First Eye Operation – Cataract Surgery 38 When the Lens Becomes Cloudy 42

In Practice Higher Quality of Life – Electronic Vision Assistant 46 Head-worn Loupes Improve Wine Quality 50 Telescopic Eyeglasses and Model Airplanes 52

Eye Care in Action Two-man Teams Provide Info on AMD 58

Prizes and Awards The Perfect Lens Material 59

Masthead 59

2 Contents Innovation 17, Carl Zeiss AG, 2006 Editorial

Dear Readers, ing eye care specialists. The first optical systems to diag- nose diseases of the eye and visual aids for various visual Eyes play a key role in how all life forms perceive and re- problems were jointly developed at the beginning of the act to their environment. A look inside the human eye 20th century together with Allvar Gullstrand who was reveals just how complicated and special it really is. The later awarded the Nobel Prize. Important, trendsetting natural lens and the cornea project our environment onto ophthalmic instruments and visual aids adaptable to the the retina. Registered and pre-processed image informa- needs of each wearer have been created throughout the tion is transmitted to the brain via the optic nerve. The 160-year history of Carl Zeiss. subsequent process of how the brain deals with this information to produce the image that we see has still not been fully researched. The superimposition and fusing of internal and external images is what constitutes the actual secret of sight. Vision is thus vital to experience, sensitivity, feelings and awareness. We generate new, personal images and points of view through reading and observ- ing, and entirely without visible objects.

Increased knowledge Carl Zeiss Meditec AG was founded in 2002, incor- The sciences of the eye, its structure and its functions porating the ophthalmology division of Carl Zeiss. The are complex and diverse. For centuries, we have tried to product offering in the field of ophthalmology and eye- explain the inner workings of the eye. Initial insights that glass lens production was expanded by the founding affect our current knowledge go back to the 18th century. of Carl Zeiss Vision GmbH in 2005. Today, Carl Zeiss is Only with the start of the 20th century did we succeed one of the world‘s leading providers of total solutions in step by step in unraveling the secrets of the visual pro- ophthalmology for diagnosis and treatment. cess. Today, recognizing and treating diseases are at the center of all activities in ophthalmology and in ophthal- Come with us and experience the world of sight and mic medical technology. visual impressions. Be amazed by trendsetting developments for the eye and read about fascinating facts & fig- Carl Zeiss plays its part ures in the use of optical instruments. Learn about the possibilities available today to preserve vision right into In a world, in which vision is becoming increasingly im- old age. portant, an impairment or even the loss of vision can mean a considerable reduction in the quality of life. The I hope you enjoy reading this issue as much as we did main causes of visual impairment, including blindness, putting it together. are ametropia (refractive errors), cataract, glaucoma and diseases of the retina such as age-related macular degeneration and diabetic retinopathy. Carl Zeiss has manufactured ophthalmic instruments for more than 100 years in close cooperation with lead- September 2006

Editorial Innovation 17, Carl Zeiss AG, 2006 3 In Focus

Sclera

Muscle Choroid

Retina

Ciliary muscle

Zonular fibers

Macula lutea Iris

Lens Pupil

Optic nerve

Cornea

The Eye

Top right: Retina of the The eye is lens. To pro- eye with blood vessels taken with the VISUCAM® an important vide protection fundus camera. sense organ of against too much human beings and light, eyes with a dia- Bottom right: Schematic drawing of the retina. many animals. For evolu- phragm – the iris – have tionary reasons, the human eye developed which can reduce the reacts to the physical stimuli of size of the pupil in strong light. electromagnetic radiation within The eye is often protected by eye- a wavelength from 350 to 750 most simple “eyes” are photosensi- lids. In order to protect it against in- nm. It then converts the stimuli tive sensory cells which function as jury, the eye is generally positioned into the perception of light and passive optical systems. They can on- deep into the skull, with protruding color. ly recognize whether the surround- bones around it providing further ings are bright or dark (Euglena, protection. Although the structures of eyes in Volvox). In some mollusks (e.g. squid) and the animal kingdom are very similar, Eyes are generally almost spherical most vertebrates, light is projected they have each developed independ- in shape. The largest part of the eye, onto the retina, a photosensitive ently of each other. This is clearly the vitreous body, is filled with a layer of sensory cells. The light per- seen in the embryonal formation transparent, gel-like substance. Many ceived by the sensory cells is con- of the eye: while vertebrates eyes animals possess eyes with a lens verted into nerve pulses which are develop from a protuberance of the whose shape can be changed in transmitted to the brain by the optic cells that later form the brain, the order to focus the image. Here, the nerve. eyes of mollusks result from an in- ciliary muscle is responsible for the version of the outer cell layer that focusing process (accommodation) subsequently forms the skin. The by changing the curvature of the

4 In Focus Innovation 17, Carl Zeiss AG, 2006 details

The human eye

Using their eyes as sense organs, humans see objects at different distances. With their eyes, they can recognize colors, shapes, sizes, distances and movements as well as the orientation and texture of objects. The object information processed by the eye consists of the visible portion – 350-750 nm – of the light spectrum. Eye Diameter of the eyeball – Adult 22 - 23 mm – New born baby 10 - 17 mm

Circumference 74.9 mm Weight 7.5 g Volume 6.5 cm³

Intraocular pressure 12 - 21 mmHg

Start of tear production from approx. the third week of life Number of retina photoreceptors (rods and cones) Pigment cells Axons of 132,000,000 ganglion cells Number of rods 125,000,000 Rods Number of cones 7,000,000 Number of retinal switching cells 2,000,000

Absorption range of the photoreceptors 350 - 750 nm Optic nerve Number of nerve fibers in optic nerve 1,000,000 Visual field Distance of near point with maximum capacity of accommodation 10 - 19 years 7 cm 20 - 29 years 9 cm 30 - 39 years 12 cm 40 - 49 years 22 cm 50 - 59 years 40 cm Cones Bipolar cell Ganglion cell 60 - 69 years 100 cm 70 - 79 years to 400 cm

In Focus Innovation 17, Carl Zeiss AG, 2006 5 The Fascination with Seeing

We equate seeing and recognizing with understanding and comprehending, and derive our “insights” from these. Without seeing, many experiences that shape our awareness would re- main incomplete. The German word for awareness, “Bewusst- sein”, has its roots in the Early High German word “bewissen” and its meaning “I have seen, I know”. The German word for seeing, “Sehen”, originates from the indo-Germanic “seku”, which means something along the lines of “to follow with the eyes”.

Below: Leonardo da Vinci’s preoccupation with optics is impressively reflected in the treatment of light and shadow in his paintings. His “Chiaroscuro” is a barely perceptible contrast between light and dark that endows his female portraits with a perfect aura of mystery.

6 In Focus Innovation 17, Carl Zeiss AG, 2006 Even the origins of these terms illus- see could not be triggered by rays of upon these theories, largely under Above: Schematic diagram trate that people examined their abil- light emitted from the eye, as other- the influence of Leonardo da Vinci’s of the eye from the Codex Atlanticus and sketched ity to see at an extraordinarily early wise it would have to be possible for optical studies. “He was like a man examinations of binocular stage – not just as a means of exter- us to see in the dark. who awoke too early in the darkness, perception from the nal orientation, but also as an inner What then is the nature of visual while the others were all still asleep,” Codex Madrid by Leonardo da Vinci. perception of themselves, their expe- perception? Inevitably, there has to wrote Sigmund Freud. riences and responses. be a meeting between an object of Leonardo da Vinci rejected the There have been a number of the- the perception and a subject per- prevailing view that the eye was able Literature: ories on visual perception throughout forming the perception. This opposi- to see by emitting rays of light. He Oliver Wondratschek, physicist: “Geschichte der history. Empedocles believed that our tion is reflected in all the theories of dissected the eyes of animals and Theorie des Sehens” Wiki- eyes contained pores, the emissions sight, with the object and subject be- probably also those of humans. He pedia, free encyclopedia. from which brought about visual per- ing emphasized to a greater or lesser drew the first schematic representa- Andre Chastel: “Leonardo der Künstler” Belser-Verlag, ception. Plato defined sensory per- extent. Roman philosophy followed tions and, with his notes on eyes, Stuttgart-Zurich, 1981. ception as an interaction between Greek philosophy, and even during pupils and binocular perception, and object and subject, referred to as the the first 1500 years of the Christian on comparisons with the workings of medium, where the two outward- calendar nothing of any significance a camera obscura, steered research moving currents meet. Aristotle rep- was added to the theories of Plato and teaching on the subject of see- resented the view that neither the and Aristotle. Followers of Plato ac- ing in a new direction – towards the detachment of images from objects cepted as fact that rays of light were beginnings of the, by no means fully nor the combination of an external emitted from the eye, while follow- complete, knowledge that we have light with an internal light made see- ers of Aristotle took his comparison today. ing possible. He believed that he had of sensory impression with the improved that light could not consist of pression left by a seal in wax as their rays emitted from objects because main doctrine. light did not require any time to trav- It was only at the beginning of el. He also believed that our ability to the 16th century that doubt was cast

In Focus Innovation 17, Carl Zeiss AG, 2006 7 Visual Perception

Three people observe events at a all. Legal statistical surveys verify busy junction. They then have to that accounts of one and the describe what they saw. The re- same observation by no means al- sult is three accounts that differ ways correspond, particularly if a greatly from each other in crucial certain amount of time has passed details. Nevertheless, all three in- between the event that was seen dividuals are certain that they saw and the account. Legal practice everything correctly and that they therefore wisely speaks of the have described everything accu- credibility of a witness statement, rately. An unlikely event? Not at and not of its objectivity.

8 In Focus Innovation 17, Carl Zeiss AG, 2006 What is the most difficult of all? That which seems to you the easiest: “To see with one’s eyes, what is lying before them.”

Goethe, Xenien, from the estate of Goethe

Vision Seeing and recognizing is an ongo- tion. The visual short-term memory is Left: Busy junction in ing learning process for the brain that where image impressions are stored Zurich, Switzerland. Visual perception is a complex process. continues for a whole lifetime. In the for fractions of minutes, while in- It is possible to appreciate its signifi- first few weeks after being born, an formation can be called up from the cance simply by considering the size infant still perceives his environment visual long-term memory even after a and number of areas in the brain that primarily through his sense of hearing number of years. are involved in capturing and analyz- and touch. It takes time for the brain ing an image. Besides the primary to learn to focus sharply on images Seeing visual cortex, which makes up around and to interpret them. The mother, for 15% of the total cerebral cortex, more example, is recognized as an attach- How do we see? White light, which than 30 different visual areas (and, ment figure, associated with pleasant contains all the colors of the spec- therefore, around 60% of the cerebral experiences. These “image experienc- trum, falls on an object. Part of this cortex) are involved in the perception es” are stored by the brain. They re- light is absorbed by the object and and interpretation of visual stimuli. main in our visual memory, are linked another part is reflected. The reflect- We divide up our overall percep- to other sensory impressions and are ed components determine the colors tion into hearing, touch, taste, smell used in our behavior. of the object. and sight – and, consequently, tend to The visual memory is divided up This light, or rather the projection speak of the five human senses. The into three main components: the of the object, is reflected into the eye. importance attributed to sight has iconic memory is where large vol- The light is bundled by the cornea and predominance. The assumption today umes of information are stored for the lens – using a process similar to is that up to 80% of all perceptions brief moments (less than a second). that of a camera lens. The pupil takes are visual or, at least, are influenced These fade very quickly, however, and on the task of the aperture. It regu- by our sense of sight. are replaced by subsequent informa- lates the amount of light that enters

In Focus Innovation 17, Carl Zeiss AG, 2006 9 Right: Two main cortical the eye. This adjustment takes place with complete images, but rather a ground. Less attention is paid to the information processing streams flow from the with the help of muscles, which di- collection of colorful points within background and it is sometimes even primary visual cortex. The late or constrict the pupil depending the boundaries set by the optics and overlooked. In eastern cultures the temporal processing stream on the intensity of light. Finally, the retina. It is only our brain that forms harmony of the whole carries high (yellow) is important for object recognition and goes object being viewed is reflected onto the image from these points. This importance. It is the overall impres- to the temporal lobes. The the retina, like onto a film in a cam- does not have to correspond entirely sion that is being sought. Asian peo- parietal processing stream era. In the retina, the image, with its to reality, as our “common sense” ple, therefore, initially pay attention to (red) is important for object isolation and the perception color components and contrasts (dif- completes the perception by means the background of the image before of movement and goes to ferences in brightness), is “recognized” of stored knowledge. This explains focusing on the central content. the parietal lobes. via chemical processes and converted why witness statements and descrip- During experiments in which stu- into electrical impulses (this process tions of observations sometimes turn dents were asked to look at an image is almost like that performed by a out to be contradictory after a certain of a forest scene with a tiger in the microchip in a video camera). The amount of time. foreground, American students fixed optic nerve, a large “bundle of cables” In addition to the above, we are their gaze on the foreground object with more than a million nerve fibers, also able to imagine how things look more quickly and for longer, while, passes on the image information to with the help of our “mind’s eye” and conversely, Chinese students focused the various centers in the brain where develop detailed descriptions relating on the scene as a whole sense is made of the image, i.e., to this type of “visualization”. what it actually depicts and how to Furthermore, the way that the con- react to it. tent of images is perceived depends What we think we see is, therefore, on the observer’s cultural background. an impression created by our brain. Members of western societies con- The eye does not supply the brain centrate more on objects in the fore-

10 In Focus Innovation 17, Carl Zeiss AG, 2006 Limits of vision this context, it is important to know perceive things that do not change References: that only a very small area of the to- Dr. Karl R. Gegenfurther, conspicuously. That is why experts Max Planck Institute for There are limits to what the human tal visual field is actually seen sharply. recommend that we should let the Biological Cybernetics, eye can do. Once objects reach a cer- This small area corresponds to the brake lights of our cars flash on and Tübingen, Germany: fovea on the retina and the size of “Visuelle Informations- tain speed it is no longer able to fol- off as we approach a traffic jam, so verarbeitung im Gehirn” low their movements. Experiments your thumb nail with your arm out- that the person driving behind also [Visual information show that, in tennis, line judges often stretched. This is the only so-called has time to recognize the potential processing in the brain], ”sharp spot”. We do not notice that Contributions for the only think that they have seen the danger. This brings our little excursion 1st Tübingen Conference point where the ball hit the ground. the rest of the visual field remains on the workings and capabilities of on Perception 1998. The off-side rule in soccer also places out of focus because the eye moves our visual perception back to where it Knirsch Verlag Kirchen- extremely high demands on the visual back and forth so quickly. The brain started from – traveling – which, sta- tellinsfurt, Germany. system, as two moving players, who puts together what you see from a tistically speaking, is something that are sometimes far apart, have to be number of ”snapshots”. The move- we spend more than a tenth of our observed at the same time, meaning ment of an object is either registered lives doing and demands high visual that two different moving points have or ”overlooked”, depending on the concentration from the person behind to be registered and, furthermore, as- attention that we are paying to it. the wheel. sociated with an imaginary line. In In particular, we can easily fail to

Parietal lobe Frontal lobe Occipital lobe

Primary visual Cortex Temporal lobe

Cerebellum Brain stem

Spinal cord

Parietal processing stream Temporal processing stream

In Focus Innovation 17, Carl Zeiss AG, 2006 11 Optical Illusions

Our brain “translates” what the eye sees into visual information – and, occasionally, also into optical illusions. Our mind is used to making sense of all the images we perceive on the basis of its visual memory and completing them by means of stored experiences. This process of “comple- tion” is what leads to optical illusions. These take the form of geo- metric illusions, color illusions, contrast illusions and others besides. A number of examples can be used to illustrate the subjective suggestibility of our visual perceptive capacities:

The relativity of straight lines

The image above consists of alternat- ing dark and light squares. Light dots have been placed in some corners of the dark squares. This creates the impression that the lines separating the light and dark squares, which we know to be straight, are warped. The second and sixth bars in the figure on the right appear to get wider towards the right-hand side of the image, while the fourth bar appears to get narrower. In fact, all the hori- zontal lines are completely parallel; none of them get wider or narrower. The figure below on the right con- veys the impression that the vertical lines are warped. In reality, they dis- sect the diagonal lines crossing them in an entirely parallel and straight manner.

12 In Focus Innovation 17, Carl Zeiss AG, 2006 The relativity of size

The photo montage on the left shows a colonnade and three pairs of people. The pair in the foreground appears smaller, while the pair in the background appears bigger. If you were to measure them, this would reveal that all three pairs are in fact the same size. It is the three-dimensional perspective and the sense of distance associated with it that con- veys the impression that the groups of people are different sizes.

The relativity of color

If you look intensively at the green square for around thirty seconds and then at the blank space next to it, a reddish field appears in the blank space. The reddish-color square appears because we see an afterimage on our retina in red, the complemen- tary color to green.

The relativity of brightness

A shade of color that we experience as bright in twilight appears dark in full sunlight. Our brain refers back to this experience when viewing the example shown. The narrow gray area within the square appears lighter on the left and darker on the right, Manfred Schindler although it is exactly the same shade [email protected] of gray all the way along.

In Focus Innovation 17, Carl Zeiss AG, 2006 13 Light-sensitive cell Eye-spot

Sensory cell Sensory cells

Human and Animal Eyes

The ability to see is a precious gift. Many living creatures find their way in their environment primarily with the aid of light. Objects become visible through many different phenomena such as refraction, reflection and the color of light. The way in which creatures see differs in regard to their shape perception, color visualization, resolution and the ability to see in three dimensions. Even plants can perceive light. However, this cannot really be termed as vision, as plants are not capable of distinguishing between colors and structures.

14 In Focus Innovation 17, Carl Zeiss AG, 2006 Pinhole camera eye

Sensory cells

Pigmentary layer

Photosensitive sensory cells (ocelli) on spot. Here, the light sensory cells are era principle. Real pinhole eyes “see” Left: Euglena protozoa. the outer skin can be seen as the sim- directly facing the light. In the pit, better than pit eyes. The opening of Center: White-spotted jelly- plest “eyes” in existence. the light sensory cells form a cell the pit is only a very small hole and fish (Phyllorhiza punctata). However, as optical systems they layer, to the inside of which a layer the cavity is completely filled with only function passively: only bright of pigment cells is connected. The pit secretion. As the number of light Right: Shellfish (Haliotis). and dark are recognized. In the con- is filled with secretion. In addition to sensory cells is considerably greater, text of a sensory organ, this can be bright-dark perception, this type of pictorial vision is possible, although seen as skin or dermal light percep- eye makes it possible to additionally very weak and dim. This type of eye tion. The protozoon Euglena pos- determine the intensity and direction is found in lower forms of cuttlefish. sesses such a light sensory cell for of incidence of light. In addition to eyes with refractive bright-dark perception. More highly If the visual cells are turned away lenses, reflective eyes also exist, al- developed creatures, e.g. the earth- from the light in a cup-shaped cell beit infrequently, e.g. in the scallop. worm, also have individual light sen- area consisting of opaque pigment The image is generated by concave sory cells at the end of, or scattered cells, the term pigment cup eye is mirrors arranged behind the retina, all over their bodies. Many adjacent used. Only the light rays entering with the lens located directly in front light sensory cells such as those through the opening of the cup can of the retina being used to correct found in coelenterates, polyps, jelly- stimulate the light sensory cells. In the pronounced optical aberrations fish and anemones, for example, can addition to bright-dark perception, of the mirror image. What seems to be described as “eyespots”. It is as- this makes it possible to determine be important in this type of eye is the sumed that the concentration of sen- the direction of light incidence. Snails light yield and not the image quality. sory cells on a certain area improves are one example of creatures that bright-dark perception. have such eyes. The pit eye can be seen as a Pit and pigment cup eyes function further development of the eye- in accordance with the pinhole cam-

In Focus Innovation 17, Carl Zeiss AG, 2006 15 Lens eye

Lens Retina

The perception of insects is excep- The most advanced light-percep- tional and totally different. They have tive organ from the human perspec- what are known as compound or tive is the lens eye of vertebrates and complex eyes that are composed of more highly developed squid. A multi- numerous simple eyes (ommatidia). step, refracting, light-collecting sys- A raster-like image is generated: tem projects the light onto the retina. here, the spatial resolving power is The retina displays two types of sen- limited by the number of image sory cells: rods and cones. Adaptation points. It is far lower than the resolu- of the eye to close-up and distant tion of the human eye. However, the objects is enabled by an elastic lens. temporal resolving power for moving processes is considerably higher. With their high speed of reaction, flying insects resolve 250 images per second. The human eye sees only about 24 images per second. In many cases, the visual field is considerably larger than that seen by humans. The third visual perception organ of insects, the ocellus, functions as a light meter used to determine brightness. The color sensitivity of the compound eye is displaced to the ultraviolet region of the spectrum.

16 In Focus Innovation 17, Carl Zeiss AG, 2006 Left: Human eye. Compound eye Right: Compound eye of the dragonfly.

Lens Crystalline cone Optic nerve

The evolution of “The human brain also still has cells The living fossil Platynereis dumerilli. the human eye that are sensitive to light and control our daily rhythm.” The object exam- Heidelberg scientists at the European ined was the “living fossil” Platynereis Molecular Biology Laboratory (EMBL) dumerilii that is practically identical to have found evidence of how the eye its 600 million year old ancestor. of vertebrates – and hence also of hu- The scientists compared the mo- man beings – has developed. In early lecular composition of the photosen- animal ancestors of humans, they dis- sitive cells in the brain of the ring- covered two types of photosensitive worm Platynereis dumerilii to those cells: rhabdomeres and light-percep- of the receptors of vertebrates. What tive cells. While in most types of ani- they found was the pigment compo- mals the rhabdomeres developed into nent called opsin both in the light- eye cells and the ciliary light-percep- sensitive cells in the brain of the tive cells did not leave their location in worm and in the visual cells of verte- the brain, the evolution of the eye in brates. The identical molecular finger- vertebrates and therefore humans fol- print is clear indication of a common lowed a different course: the ciliary evolutionary origin. light-perceptive cells became visual cells. “Evidently, our visual cells – the rods and cones – originate in the brain of a mutual ancestors of worms and humans,” explains Jochen Wittbrodt www.db.embl.de from the research team and adds: www.platynereis.de

In Focus Innovation 17, Carl Zeiss AG, 2006 17 MusterseitenMilestones

Luxury Article or Basic Commodity?

Glass is an amorphous, non-crys- Glass is one of the oldest known ma- lightning is known as fulgurite. Ob- talline substance as old as the terials and is used today, as in the sidian is volcanic in origin. earth itself according to the sci- past, both as a luxury item and a ence of today. The creation of basic commodity. Glass can be proc- No end to the glass requires very high tempera- essed into lenses for optical instru- possibilities tures such as those generated by ments such as eyeglasses and objec- a volcano, lightning and possibly tive lenses. Today, artificial glass is divided into a meteorite impact. Thermody- Glass occurs naturally when sand ordinary glass (calcium sodium bicar- namically speaking, glass can be melts. This includes impact glass and bonate), fused quartz (pure silicon described as a frozen or under- tektites such as those resulting from dioxide), lead glass, borosilicate glass, cooled liquid. a meteorite impact. Glass created by special glass made of borophosphate

Visual devices and eyeglass lenses at Carl Zeiss

1908 1912 Moritz von Rohr calculated the first magnifying Gullstrand-type point-focal lenses are introduced by Carl Zeiss visual aid using the Gullstrand imaging theory of under the registered name Punktal®. Additional, Punktal lenses image formation: telescopic glasses. are trademarked.

1910 1914 Gullstrand-type point-focal cataract lenses, The product line is expanded to include prismatic Punktal lenses, the Katral lenses, are the first aspheric lenses as well as Supral and Infral lenses, and point-focal bifocal lenses in the world. which are also known as dual power Punktal lenses.

18 Milestones Innovation 17, Carl Zeiss AG, 2006 and aluminum silicate and non-oxidic The first record of glass produc- fluoride and chalcogenide glass. Lead tion comes from a cuneiform tablet details glass which protects against electro- from the period around 650 B.C.: magnetic radiation, borosilicate glass “Take 60 parts sand, 180 parts ash which is highly resistant chemically from seaweed, 5 parts chalk – and Eyeglass lens and thermally stable, and fluoride you get glass.” Around the time of glass are primarily used for industrial Christ, Syrian glassmakers made the The refractive power of a lens is and optical purposes. Optical glass is decisive breakthrough: the invention given in diopters (D). called crown glass (lead-free alkali- of the blowpipe and the glass kiln. calcium glass) as well as hard, mirror They revolutionized the technique of Hyperopia – when the refractive or crystal glass. It has a high percent- glassmaking. In addition to simple, power of the eye is too low – is age of potassium oxide and has been bellied containers, it was now also corrected using plus lenses. Plus known for centuries. The name itself possible to produce thin-walled and lenses – spherical lenses – have is derived from the oldest process of fine glass in various shapes. The use a positive meniscus and thus manufacturing window glass in Eng- of the blowpipe was also the first a “collecting” effect. They are land. Additionally, reflection-reducing step in manufacturing flat glass. designated with a plus sign coatings are added in many optical (e.g. +1.75 D). instruments. Across the globe People with myopia have eyes Accidental discovery The well-developed trade relation- with a refractive power that is too ships among the peoples of the Ro- high. Minus lenses are used for The possibility of manufacturing glass man Empire were decisive for the correction. Minus lenses, spherical was discovered by chance: sodium-bi- spread of glassmaking. Glass factories lenses, have a negative meniscus carbonate glass was created from the sprang up in Spain, Gaul and Germa- and thus a “dispersing” effect. fusion of calciferous sand while bak- nia. In his “Naturalis Historia” Pliny They are designated with a minus ing crockery. Colorful glazes on finds the Elder described the composition sign (e.g. -0.5 D). in the Orient which have been dated and manufacture of glass. to the 7th century B.C. indicate that In the 1st century A.D., citizens of A combination of plus and minus the manufacture of glass is closely Alexandria using advanced furnaces lenses helps people with presbyo- related to pottery. Glass pearls from made colorless glass for the first time pia. Simple designs are known as 4th century B.C. Egypt are considered by adding manganese oxide. Roman bifocals in which the plus lens is to be the first glass products. Egyp- glass made it to China via the Silk the lower lens. They are referred tian glassmakers probably already Road although glassmakers had al- to as progressive lenses when the began producing jewelry and small ready existed there for years. transition from minus to plus is glass containers, which were mod- not visible. eled around a solid sand or clay core, Manufacturing 3000 years B.C. in transition Egyptian glass containers, such as jars for ointments and oils from At the end of the 6th century, Franco- the time around 1500 B.C. lead to nian Bishop Gregor von Tours men- the conclusion that this was the be- tioned church windows made of glass ginning of glass production without in his “Historia Francorum”. Findings ceramic supports. on the island of Torcello near Venice

1924 1927 1933 1952 ZEISS near-vision glasses URO-Punktal lenses protect A new style of glasses is Duopal® eyeglass lenses are with Punktal lenses for people against ultrared light. launched with the Perivist frames considered a revolution in bifocal with presbyopia. for unhindered lateral vision. lenses.

1926 1928 1935 Contact lenses for the Umbral lenses are now available with a color The invention of the coating procedure correction of keratoconus. wedge. One year later, these lenses are available for glass surfaces to reduce reflections at as grayish-brown ZEISS Gradal antiglare lenses. Carl Zeiss is patented.

Milestones Innovation 17, Carl Zeiss AG, 2006 19 Fused silica, prove that the manufacturing tech- Glass for use as a construction mate- ing constantly expanded: improved silicon dioxide. nology changed in the early Middle rial was presented in Berlin in 1931 anti-reflective coatings, dirt-resistant Ages. Potash (calcium carbonate) was at a building exhibit. Cellular glass for coatings and hard coatings are now increasingly used in glassmaking. In insulation purposes followed in 1932: available. his 12th century writings “Schedula 1934 saw the introduction of the ex- diversum atrium”, Benedictine monk tremely temperature-resistant Vycor Broad spectrum Theophilus Presbyter described vari- glass. Organic glass (fully synthetically ous craftwork techniques, includ- produced plastic) was produced for Polarizing lenses suppress and reduce ing the manufacture of flat glass. In the first time in 1940. Today it is gen- light reflections and mirroring on wa- 1556, Georgius Agricola described erally used for eyeglass lenses. The ter or metal surfaces, for example. the furnaces for glass in “De re me- first photochromic glass ceramics en- The eye does not have to adjust to tallica”. The forest glass works were tered the market in 1950; photochro- different lighting conditions as often dominant in Germany between 1300 mic lenses were added in 1964. Fiber and does not tire as quickly. An addi- and 1700. With up to 8000 people in optics, which Pozzini had already tional coating on anti-reflective lenses the glass works, Venice became the described in 1804 for endoscopic reduces reflections on the lens itself center of European glassmaking. purposes, have been used in modern and more light passes through the Glass for eyeglasses, simple micro- news technology since 1965. The de- eyeglasses. scopes and telescopes was manufac- velopment of the successful Ceran® Photochromic lenses which darken tured from about 1250. glass ceramics began in 1970. and brighten within seconds depend- Fraunhofer began examining the ing on the amount of light help light- scientific aspects of glass melting in Coating optimization sensitive eyes. Benediktbeuren. This resulted in glass Clean Coat helps against water with improved properties that was Working at Carl Zeiss, Smakula de- and dirt: elastic hard coatings protect used in cooperation with Guinand veloped a completely new, patented plastic material against scratches and and Utzschneider in optical instru- method in 1935 to minimize annoy- other mechanical action. ments around 1800. Schott con- ing reflections on optical surfaces: he Additionally, the latest generation ducted significant research into the added an additional coating – which of eyeglass lenses can be equipped manufacture of glass with constant was also very durable – to the surface with moisture repellent finishes. and pre-determinable optical prop- of a lens, which had an anti-reflection Steam, fog and rain easily bead off erties. In 1884, Otto Schott, Ernst effect. Smakula’s work is the basis of the lens. In 2004, a natural princi- Abbe and Roderich Zeiss founded the the standard procedures used to min- ple led the way: Carl Zeiss introduce Glass Laboratory in Jena which later imize reflections today. the LotuTec® coating. This optimized became the Otto Schott & Genossen The quality of coatings has stead- broadband anti-reflective coating is a Glass Works. ily increased since the introduction of six-layer coating. Residual reflections Advanced machines and ovens, dip hard coating at Carl Zeiss in 1986 are reduced to a minimum. together with sophisticated manufac- and today has a very high standard. Mirror coatings are achieved turing procedures quickly led to the Precisely matched coating thickness through the vaporization of inter- development of new glass products ratios of the anti-reflective coatings, ference coatings in a vacuum. Unlike such as glass permeable to ultraviolet and an exactly defined temperature anti-reflective coatings whose reduc- rays (1903), neon tubes (1904) and profile during vacuum deposition tion of reflections is attained through laminated safety glass (1905). ensure constant quality and repro- destructive interference, constructive Schott manufactured heat resist- ducibility of the anti-reflective coat- interference can lead to mirroring. ant glass products beginning in 1915. ings. The coating procedures are be- Varying thicknesses of interference

1959 1970 1978 Eyeglass lens coating to reduce reflections is Introduction of the Umbramatic® Plastic lenses are dyed using introduced for glass lenses as the ET® coat. photochromic eyeglass lenses which the dip method. adjust to lighting conditions.

1965 1974 ® Carl Zeiss launches Clarlet® plastic Tital eyeglass lenses made of highly eyeglass lenses made of CR 39. refractive Schott glass for severe ametropes.

20 Milestones Innovation 17, Carl Zeiss AG, 2006 details

Visual field

The area captured by an eye without eye movement is described as the visual field. The visual field of both eyes in adults is approximately 190° horizontally and approximately 150° vertically. Only moving objects are perceived in the peripheral region (~10°).

Flies with compound eyes have a visual field of almost 360°. Frogs can see 330° and kestrels more than 300°. The field of view of barn owls is only 160°.

coatings result in different reflection Top: Multi-layer coating colors. structure. As a result of their low density, Bottom: Patent for the plastic eyeglass lenses are extremely procedure developed light. However, organic eyeglass lens by Smakula to reduce reflections. material is relatively soft on the surface and therefore not very scratch- resistant. In order to nonetheless satisfy the highest demands, plastic lenses are sealed with a hard coat.

1983 1989 Horizontally symmetrical Gradal HS® progressive Carl Zeiss adds the high index lenses are launched. Introduction of a new trademark Lantal® lens to its product line. on all eyeglass lenses.

1986 1986 Hypal®, the aspherically and atorically structured First dip hard coatings are developed for eyeglass lens, permits the manufacture of flat Clarlet® lenses: 10 years later it is the indispensable lenses and is exclusively produced by Carl Zeiss. standard coating on plastic lenses.

Milestones Innovation 17, Carl Zeiss AG, 2006 21 The Early Days at Carl Zeiss

The lenses in a pair of eyeglasses Eyeglass lens new findings were known as Katral correct defective vision. As the optimization lenses and were developed for eyes oldest product of its Optics de- that had no crystalline lens as a result partment, Carl Zeiss sold glasses Consequently, in 1908 the board un- of cataract surgery. These were fol- in its own store until 1880. The der Rudolf Straubel entrusted one of lowed in 1912 by lenses that provid- ophthalmologist Allvar Gullstrand its scientists, Moritz von Rohr, with ed point-focal images in every view- encouraged Carl Zeiss to further the task of investigating possible im- ing direction: Punktal lenses. These pursue the subject of sight. Abbe’s provements to eyeglass lenses. He lenses were not just an improvement theory of ray limitation was sup- worked in close contact with Allvar over the eyeglass lenses that had plemented by Gullstrand‘s infor- Gullstrand and with Hans Boegehold been available up until then, but they mation on vision with the moving to create new computations for eye- also constituted a breakthrough in eye. glass lenses. The first eyeglass lenses eyeglass technology: the Punktal to be computed according to the lenses were the first lenses to be

1993 1995 1996 Skylet®, the sun-protection lens Carat®, the high-quality coating system for plastic Gradal® Top progressive lenses with targeted blue filter for better lenses combining hard-coat, broadband anti-reflective for smooth, natural vision from color contrast. and Clean Coat. near to far.

1994 1995 Gradal HS® with OSD (Optimum Surface Design): Carl Zeiss introduces the new sunglass lens atoroidal surface design for progressive lenses with Cool Blue mirror coating which reduces delivers even better image quality. light by 85 percent.

22 Milestones Innovation 17, Carl Zeiss AG, 2006 computed on a strict scientific basis. In order to be able to manufacture Depending on the refractive power, large quantities of eyeglass lenses and details the curvature of the lens can be guarantee high quality, new efficient defined so that the oblique astigma- production methods were developed tism can be totally corrected for pe- by Rudolf Linke with newly designed ripheral rays. tools, fixtures and machinery. From Contact lenses 1924 onwards, the production of Industrial manufacture anti-glare lenses with the name Um- The idea of a lens that could be bral began. The Uro-Punktal lens for worn directly on the eye was Von Rohr soon realized that the only the protection of UV-sensitive eyes described as far back as 1636, way for Carl Zeiss to generate a profit expanded the product range from more than 350 years ago, by René would be by the mass production of 1927, with the bifocal lenses then Descartes (1596-1650). However, quality eyeglass lenses over the long completing the offering: the bifocal this idea was not pursued further term. He also used lectures, confer- short-distance lens ‘Supral’, the bifo- until the end of the 19th century ences, and courses for ophthalmolo- cal long-distance lens ‘Infral’ and the by the physiologist Adolf Eugen gists and opticians to publicize the bifocal lens ‘Tangal’ with its barely Fick (1829-1901). Zeiss eyeglass lenses. From 1912 visible dividing line. During this time, onwards, Otto Henker also took an the production and sale also began After making plaster casts of rab- interest in eyeglass lenses. And, on of so-called “contact lenses” to cor- bit eyes, he had lenses made that April 1, 1912, the Optics department rect defective sight caused by defor- he tried out on himself, tolerating was founded for the new eyeglass mation of the cornea. them for more than two hours. business. In 1917, at the suggestion Eyeglass frames were initially only He tried the method successfully of Henker and von Rohr, the Jena made for special devices, e.g. x-ray on 17 patients before publishing State College for Ophthalmology adjustment, heat protection and tel- his work, “Eine Contactbrille”, was established to provide system- escopic glasses. In 1932, systematic in 1888. atic training for optometrists. The production began with the construc- first head of the college was Gerhard tion of the Perivist frame, on which In Jena in 1912, Carl Zeiss began Kloth, who was followed by Her- the temples were anatomically adapt- the manufacture of reproduc- mann Pistor. ed to the ears. ible, ground contact lenses. Initial steps on the path toward plastic lenses, and therefore smaller and more compatible contact lenses, followed: in 1918, Carl Zeiss received a patent for contact lenses made of celluloid and began producing “corneal lenses”. From around 1928 onwards, the use of acrylic glass (polymethylmeth- acrylate (PMMA)) combined with a reduction in diameter to roughly 10 mm made it possible to wear the contact lenses for 10 to 12 hours a day.

2000 2003 2006 Gradal® Individual progressive Product innovation: Gradal Individual® FrameFitTM lens can be customized to the SkyPol® sunglass lens. progressive lens – the new freedom for eyeglass wearer. designing progressive lenses with smooth progressive zones without dividing lines.

2002 2004 Clarlet® Transitions fast, The Lotus effect is the basis for the development photochromic plastic lenses of dirt-resistant LotuTecTM surface coating for introduced. plastic lenses.

Milestones Innovation 17, Carl Zeiss AG, 2006 23 A Tradition of Innovation

Top: The Verant magnifier Although the eye is particularly The early days Allvar Gullstrand, which began in (left) developed by accessible for optical examination 1901, was undoubtedly a stroke of Moritz von Rohr based on the ideas of Gullstrand. methods, the diagnostic possibili- The first ophthalmologic instrument luck for the further positive develop- Czapski’s binocular corneal ties available to the ophthalmolo- at Carl Zeiss was a monocular cor- ment of ophthalmologic instrument microscope (1889). gist were extremely limited until neal microscope dating from 1893, design at Carl Zeiss. Allvar Gullstrand the end of the 19th century. It was constructed in accordance with the possessed extraordinary knowledge not until 1850 that Hermann von specifications of the Dresden oph- in the field of optics, particularly the Helmholtz invented the ophthal- thalmologist Fritz Schanz. A signifi- optics of the human eye. moscope, which made it possible cantly improved binocular corneal Gullstrand visited Jena for the first to look into the interior of the microscope with an illumination de- time at Czapski’s invitation in August living eye. The year 1850 can be vice was subsequently developed by 1901. During this visit, Gullstrand regarded as the dawn of modern Siegfried Czapski and presented in suggested that an observation mag- ophthalmology, and the year in 1898. nifier adjusted to the eye’s center of which the construction of oph- The basis for this was a stereomi- rotation be computed with a large thalmologic instruments began. croscope that had been manufac- distortion-free field of view. He re- For more than 100 years, Carl tured at Carl Zeiss since 1897, which quired such an instrument to enable Zeiss has been successfully shap- had been developed together with him to evaluate photographic images ing the ophthalmologic instru- the biologist Horatio S. Greenough. with a high degree of precision. This ment design with its innovative The basic optical concept of the task was fulfilled brilliantly by Moritz products. Fundamental to this Greenough-Czapski corneal micro- von Rohr through the computation of success has been, and still is, the scope is still used today – in a virtually the “Verant magnifier” (1903). close collaboration of scientists unchanged form – in many slit lamp With the Verant magnifier, the im- and engineers at Carl Zeiss with instruments. portance of the eye’s center of rota- outstanding ophthalmologists and However, the close collaboration tion in the combination of an optical optometrists. with the Swedish ophthalmologist, instrument with the moving eye, a

24 Milestones Innovation 17, Carl Zeiss AG, 2006 principle initially discovered by Allvar ment was also created on the same ment for photographing the fundus Gullstrand, was taken into account in day. The first scientific head of these that was suitable for practical use. instrument design for the first time, two departments was Otto Henker. Following the early death of Otto therefore triggering the subsequent The large ophthalmoscope and Henker, the scientific leadership of successful development of other opti- slit lamp were of considerable im- the department was taken over in cal instruments. portance in the field of ophthalmo- 1926 by his former employee Hans logic examination instruments. They Hartinger, who continued to develop Scientifically enhanced the diagnostic options for the product line. computed – Punktal the ophthalmologist quite remarkably 1930 saw the introduction of and were unrivalled for decades. Amsler’s photokeratoscope, which Building on these results, from 1904 Gullstrand‘s “large ophthalmo- enabled the photographic recording onwards, von Rohr began the first scope” was the result of the system- of the surface shape of the cornea. preliminary mathematical work to atic ongoing development of Helm- The underlying measurement princi- solve the problem of point-focal eye- holtz’s ophthalmoscope. Equipped ple – the projection of a ring struc- glass lenses. From 1908, together with with an aplanatic, aspheric ophthal- ture – is still applied today in modern Hans Boegehold and later August moscope lens, it allowed reflex-free corneal topography instruments. Sonnefeld, he developed the famous observation of the fundus of the eye. In 1933, at the suggestion of the Zeiss Punktal lenses. Punktal lenses, The slit lamp proposed by Gullstrand Rostock ophthalmologist Comberg, the first eyeglass lenses computed on made it possible to visualize the nor- the slit lamp was arranged vertically a strictly scientific basis, were launched mally invisible, transparent anterior and connected with the corneal mi- on the market in 1912 and enjoyed segments of the eye – the cornea croscope via a common axis of rota- incomparable success all over the and lens – with particular clarity using tion, the vertical line of extension of world. what is known as focal illumination. which ran through the eye that was to be examined. The result was an Pioneers of ophthal- Systematic extremely compact slit lamp instru- mologic instruments development ment that was easy to operate. Together with Luigi Maggiore, an The continued collaboration with The comprehensive product range ophthalmologist from Rome, a pro- Gullstrand subsequently resulted in a that already existed when the depart- jection perimeter – an instrument for virtually complete range of visual aids ment was established was quickly de- determining the visual field of glauco- and in a series of new ophthalmologic veloped and expanded under the ma patients – was developed in 1935. examination instruments. guidance of Henker and in close part- The innovative aspect of Maggiore’s Gullstrand not only provided the nership with scientists and ophthal- projection perimeter was that the test stimulus for the development of new mologists. targets, whose brightness, color and instruments but also usually supplied In 1915, at the suggestion of the size could be adjusted as required, the basic opto-mechanical concept ophthalmologist Leonard Koeppe, the were no longer moved physically and for their implementation and was al- Gullstrand slit lamp was combined laboriously, but instead were pro- ways a critical partner during clinical with Czapski’s corneal microscope, jected onto the perimeter arc using a trials. Von Rohr acted as the expert thereby creating the prototype of the intermediary between Gullstrand and “slit lamp” examination instrument. the Zeiss production facilities, in ad- Gullstrand‘s simplified large oph- dition to being his most important thalmoscope was presented in 1919. colleague in the field and closest Henker’s parallax refractometer was Brief biograph confidant. The technical realization subsequently developed on the ba- of Gullstrand’s ideas in the form of sis of this instrument in 1922 – this Allvar Gullstrand (1862 - 1930) instruments initially took place in a was the first instrument for objective First Professor of Ophthalmology at specially created temporary depart- refraction of the eye. The develop- the University of Uppsala in Sweden. ment headed by Otto Henker. It was ment of Nordenson’s retinal camera, Close collaboration with Carl Zeiss from this department that, on 1 April which was based on the principle of from 1901. Received the Nobel Prize 1912, the department of Medical Op- the simplified ophthalmoscope, was in Medicine (1911) for his work on tical Instruments was established. The of exceptional significance. It was the the optical properties of the eye. closely associated Eyeglass depart- first industrially manufactured instru-

Milestones Innovation 17, Carl Zeiss AG, 2006 25 Left: Gullstrand’s large small, pivoting projection instrument, Innovation on ments in particular, he rendered out- ophthalmoscope for and simultaneously recorded. separate paths standing services to the industry. monocular observation (1911). Comberg‘s nyctometer produced An early, extremely successful from 1939 onwards was an instru- When Germany was divided at the product was his new slit lamp, manu- Right: Nernst slit lamp ment for determining adaptability end of the Second World War, the factured from 1950, which displayed designed by Gullstrand (1912). and glare sensitivity. It was the first in- development of Carl Zeiss in Jena and a number of advantages in com- strument that was able to determine Oberkochen also followed separate parison to Comberg‘s slit lamp: the twilight visual acuity and was used paths. In Jena, after the total disman- slit image projector could be moved primarily for testing the suitability of tlement of the production facilities, freely on an arc in front of the micro- pilots and motorists. the most important instruments from scope during observation. Behind the the pre-war period were initially re- objective lens, the microscope had a constructed and further developed parallel beam path in which Galilean under the leadership of Ferdinand telescopes were mounted as magnifi- Fertsch and Edzard Noteboom. At the cation changers. new facilities in Oberkochen, how- 1950 was also the year in Brief biography ever, use was made of the opportu- which Littman‘s ophthalmometer was nity to make a completely fresh start. launched. It ideally satisfied the re- Moritz von Rohr (1868 - 1940) Hans Littman, who was forced to quirements for an error-free ophthal- Studied mathematics, geography, move from Jena, developed the Medi- mometer formulated by Helmholtz history and physics. Worked at cal Optical Instruments department in and, in terms of its measuring accu- Carl Zeiss, Jena, from 1895. Assistant Oberkochen with great success. From racy, is unsurpassed even today. to Abbe and Rudolph. Specialized in 1946 until his retirement in 1973, he In 1953, Hans Littman completed photographic optics, microscopy and was the scientific head of this area the development of the OPMI® 1 magnifiers. Close collaboration with and, through his systematically well surgical microscope, which resulted Gullstrand from 1901. thought-out developments of instru- from a suggestion by the Tuebingen

26 Milestones Innovation 17, Carl Zeiss AG, 2006 1898 Czapski’s 1922 Henker’s parallax refractometer binocular corneal for testing visual acuity microscope 1920 Focimeter 1935 Maggiore’s projection perimeter

1911 Gullstrand’s large 1933 Comberg’s Comberg’s ophthalmoscope slit lamp nyctometer

1919 Gullstrand’s simplified 1934 Hartinger’s ophthalmometer large ophthalmoscope for the measurement of corneal radii of curvature

1912 Gullstrand’s slit lamp 1925 Nordenson’s retinal camera

ENT physician, Horst Wullstein. It was Littman in collaboration with the Hartinger‘s coincidence refracto- used successfully in eye surgery for ophthalmologist Meyer-Schwickerath. meter (KORE) was launched on the the first time by Heinrich Harms of This instrument wrote medical history. market in 1953. It enabled objective the Tuebingen University Eye Clinic in It was the first industrially manufac- eye refraction through the manual Germany. The optical system featur- tured surgical instrument using light coincidence setting of test targets on ing a parallel beam path and Galilean for the treatment of eye diseases. the retina. magnification changer corresponded With the inception of the light co- With the Retinophot, the retinal to that of the corneal microscope of agulator, photocoagulation became camera product line was launched the slit lamp dating from 1950. With the therapy of choice for many sight- again in 1956. In 1968, the RCS/ the OPMI 1, the foundation stone threatening diseases. RCM 310 wide-angle retinal camera for modern micro-surgery was laid Despite adverse conditions, the ar- was presented. It was the first wide- and the extremely successful devel- ea of optical medical technology was angle camera with which it was also opment of surgical microscopes in rebuilt and expanded in Jena, result- possible to photographically capture Oberkochen was begun. ing in the emergence of remarkable a retinal area of exactly 60° in In 1955, Littman presented a total- instruments for the ophthalmologist addition to image angles of 20° ly re-designed fundus camera for the and optometrist. and 40°. first time. It featured an image-side Production recommenced in 1949/ A diagnostic unit was realized for telecentric beam path and imaged a 50 with the new slit lamps in the the first time in 1960 with the design retinal area of 30°, flatly and without microscope variants PM XVI and SM of an ophthalmologic workstation aberrations. An electronic flash served XX. These slit lamps were constantly (OAP). A significant development of as the light source, greatly reducing enhanced to meet the growing de- this instrument type was the OAP the blur caused by movement. mand in the area of eye diagnostics. 211/311, manufactured from 1985, One of the most outstanding The RSL 110 routine slit lamp ad- in which the five most important in- innovations was doubtless the light vanced to become one of Jena’s most struments for the ophthalmologist coagulator from 1957 developed by successful slit lamps. (plus an automatic phoropter and

Milestones Innovation 17, Carl Zeiss AG, 2006 27 1953 OPMI 1® surgical 1960 First ophthalmologic 2003 MEL 80 laser system microscope workstation for refractive surgery Hartinger coincidence refractometer 1996 FF 450 fundus camera 1955 Littman‘s 1993 Optical fundus camera Coherence Tomograph (OCT)

1957 Meyer-Schwickerath’s xenon 1999 IOLMaster® for contact-free light coagulator – the world’s measurement of the eye first instrument for surgery using light Laser system for photodynamic 1950 Littmann’s slit lamp 1968 60° wide-angle therapy of macular degeneration and ophthalmometer retinal camera

focimeter) were combined in one with which it had been so successful cameras such as VISUCAMPRO NM now compact unit. up to that point, while Jena assumed complete the product spectrum. product responsibility for the ophthal- From 1998 onwards, the VISULAS United to achieve mologic diagnosis instruments and, type laser therapy instruments were optimum performance later, laser therapy instruments. In completely reworked and supple- 1992, a joint development team from mented with the VISULAS 690 laser After the reunification of the two Jena and Oberkochen began revising instrument for the photodynamic companies at the end of 1991, the and enhancing the slit lamps. therapy of age-related macular de- virtually identical product ranges were In 1996, with the FF 450, a high- generation. The VISULAS YAG, now divided up. Oberkochen concentrated performance instrument with excel- in its 3rd generation, is the most on the operating microscope business lent imaging properties was devel- widely used photodisruption laser for oped in the area of fundus cameras. the treatment of secondary cataract It was the first fundus camera to have across the world. its optical concept geared entirely to The most noteworthy innova- the needs of modern electronic image tion of the last 30 years in the field Brief biography sensors. In order to optimally utilize of diagnosis instruments is the IOL- the opportunities presented by digital Master® from Carl Zeiss which was Otto Henker (1874 - 1926) image production, the VISUPAC® im- introduced in 1999. This unrivalled Studied natural sciences in Jena. age archiving and processing system instrument is used for the non-con- From 1903 onwards, member of was developed to meet the special tact optical measurement of the eye scientific staff at Carl Zeiss Jena: study needs of ophthalmologists through and computation of intraocular lens- of optical lenses. Head of the newly intuitive application software. This es (IOL) for cataract operations. A co- established “Medical Optical Instru- makes it one of the most successful herence-optical measuring principle ments” and “Eyeglass” departments fundus cameras ever to be developed developed by Adolf Friedrich Fercher from 1912. at Carl Zeiss. Non-mydriatic fundus (University of Vienna) is applied for

28 Milestones Innovation 17, Carl Zeiss AG, 2006 H

A-A Axis of the eye S Corneal vertex F1 Anterior focal point F2 Posterior focal point H Principle plane of N the corneal system H1 H1 Anterior principle point H3 F2 of the overall system F1 H2 Posterior principle point A A of the overall system H3 Anterior principle point S of the lens system H4 H4 Posterior principle point of the lens system H2 N Fovea

determining the length of the eye. In tical coherence tomograph (OCT), made in 2005 through the acquisition comparison to the previous eye meas- which made it possible to obtain of the French company Ioltech, which, urement technique using ultrasound contact-free, high-resolution cross- besides intraocular lenses (IOL), also (ultrasound biometry), optical biom- sectional images of the living eye for offers all the resources necessary for etry offers a large number of advan- the first time. The previous two-di- cataract and refractive lens surgery. tages. The instrument has therefore mensional inspection of the fundus of The ideally matched instruments become accepted as the gold stand- the eye using an ophthalmoscope or of Carl Zeiss Meditec AG for the ard in biometry and is regarded as fundus camera is enhanced by the 3rd diagnosis and therapy of cataract and the most significant innovation of the dimension. Based on this extremely glaucoma, retinal diseases and visual last 30 years in the field of cataract positive development, the ophthal- defects mean that today, after more surgery. mology divisions in Jena and the USA than 100 years of successful innova- were combined and, in July 2002, tion history, Carl Zeiss is a leading Improving perform- merged with the Jena-based com- supplier of ophthalmologic instru- ance through strate- pany Asclepion Meditec AG to form ments and services throughout the gic alliances Carl Zeiss Meditec AG headquartered world. in Jena – the first company of the In 1993, Humphrey Instruments, a Carl Zeiss Group to be publicly listed US subsidiary of Carl Zeiss, acquired since 1945. the licensing rights to what is known The acquisition of Asclepion Med- as optical coherence tomography itec AG saw the development of the – a new, imaging technique based on Refractive Surgery business unit. The short-coherence interferometry – from first Carl Zeiss refractive laser system the Massachusetts Institute of Tech- was the MEL 80™ of 2003. An ideal nology. From this, in 1996 Carl Zeiss addition to the Refractive Surgery and Karl-Heinz Donnerhacke, Jena developed the highly innovative op- Cataract business units was finally

Milestones Innovation 17, Carl Zeiss AG, 2006 29 Enhancing Vision with Refractive Surgery

Defective vision, or “ametropia”, the cornea (conductive kerato- thin incision is first made in the top is caused by a disproportion be- plasty, laser thermokeratoplasty) layer of the cornea and this corneal tween the refractive power of the Ⅲ implanting an additional lens (pha- flap is lifted. Then, as with PRK, tis- cornea and crystalline lens and kic IOL) into the anterior or poste- sue is removed from the exposed cor- the length of the eye. rior chamber of the eye in front of neal stroma using the laser. Once the the crystalline lens or modeling is complete, the corneal The traditional methods used to cor- Ⅲ replacing the natural lens with an flap is closed again. With LASIK, un- rect visual defects involve placing a artificial lens (refractive lens ex- like PRK, the epithelium is retained corrective lens (eyeglass lens or con- change, RLE), as in normal cataract and does not have to grow back. The tact lens) in front of or on the eye. surgery. wound-healing process is therefore Recently, however, it has also be- shorter in the case of LASIK. Howev- come possible to perform this opti- Laser-supported er, both procedures are comparable cal correction directly in the eye it- modeling of the cornea in terms of the refractive outcome. self. As this usually requires surgical For the correction of myopia intervention, these new techniques The dominant refractive-surgical tech- (shortsightedness), the surface of the have been grouped together under nique is the laser-supported modifica- cornea needs to be flattened at the the collective term “refractive sur- tion of the shape of the cornea (PRK, center using laser ablation, whereas gery”. LASIK). for hyperopia (farsightedness) it is At present, the most important re- With PRK (photorefractive kera- steepened. The precision required here fractive-surgical techniques are: totomy), the top layer of the cornea is illustrated by the following numeri- Ⅲ correcting the refractive power of (epithelium) is removed prior to laser cal example: for a myopia correction the cornea through the targeted ablation. The underlying corneal lay- of 1D, the cornea is ablated by only modification of the corneal sur- ers (stroma) are then modeled using 12 µm at the center of an ablation face using ablative laser techniques the laser in a computer-controlled zone 6 mm in diameter. (PRK, LASIK) or through thermally procedure. In the case of LASIK (laser Modern refractive lasers – such as induced changes in the shape of in situ keratomileusis), an extremely the MEL 80 TM – are able to model

30 Milestones Innovation 17, Carl Zeiss AG, 2006 the cornea in the sub-micrometer Ⅲ a high-performance laser system the inside of the cornea to the crys- range. This makes it possible to cor- with which the new corneal shape talline lens) is sufficient. rect not only spherocylindrical aber- that has been calculated can be There are several techniques for rations (defects) of the eye (myopia, generated precisely, stably and as diagnosing disorders in and measur- hyperopia and astigmatism), but also quickly as possible. ing the anterior segment of the eye: higher order aberrations. This opens a slit lamp with a device for recording up the possibility of a further im- Refractive lens the depth of the anterior chamber, provement in vision that cannot be implants light-section and ultrasound tech- achieved using traditional methods niques and imaging using optical such as eyeglasses and contact lenses. The implant techniques (phakic IOL, coherence tomography. There are at least four decisive refractive lens exchange) are suit- In principle, there are no differenc- factors for optimum refractive correc- able in particular for the treatment es between refractive lens exchange tion: of very severe visual defects that and standard cataract surgery as far Ⅲ precise determination of the existing cannot be corrected at all using laser as the surgical technique is con- aberrations of the eye (aberrometry) ablation and only to an insufficient cerned. However, as achieving opti- Ⅲ exact measurement of the shape of degree using eyeglasses or contact mal postoperative visual acuity is the the cornea prior to ablation (topog- lenses. top priority in refractive-surgical pro- raphy) In the case of a phakic IOL, a cedures, the planning and actual per- Ⅲ intelligent software algorithms to check must be carried out before the formance of the technique must calculate the individual ablation operation to establish whether the meet more stringent requirements. profile from the aberrometric and patient’s eye will allow the implanta- For the exact measurement of the eye topographic data and to control tion of an anterior chamber lens. The and the selection of a suitable IOL, it the excimer laser so that the de- procedure is only possible if the ante- is advisable to perform optical biome- sired profile is obtained rior chamber depth (distance from try using the IOLMaster®.

Top: CRS-Master diagnostic and planning platform for patient-specific corneal modeling using the MEL 80.

Middle: MEL 80 excimer laser for refractive corneal surgery.

Top right: Cross-sectional image of the anterior chamber of an eye with a phakic IOL (image captured using the Visante® OCT from Carl Zeiss).

Bottom right: Phakic posterior chamber lenses (PRL®) for the treatment of myopia and hyperopia.

Karl-Heinz Donnerhacke, Jena

Milestones Innovation 17, Carl Zeiss AG, 2006 31 The Sensitive Sensor

The retina is the eye’s optical ing density in the center of the sensor. It is an upstream area of macula – in the area known as the brain. It captures light stim- the fovea (approx. 170,000 cones/ uli and partly preprocesses them. mm2). The fovea is where vision is The photosensitive receptors of at its sharpest. Outside the macu- the retina are the rods and cones, la, cone density, and therefore al- which differ in form and function. so visual acuity, decrease rapidly. The ability to see color during the When we fixate an object in our day is made possible by the 6 to environment, movements of our 7 million cones, which are sensi- head and eyes ensure that the tive to blue, green or red light. image of the object is located on The 120 million or so rods convey the fovea. Loss of central vision scotopic vision and contrast vi- in the macula therefore seriously sion or, during the day, enable us impairs quality of life, although to perceive movement at the pe- the person affected is not totally riphery of our field of vision. The blind. photoreceptors are distributed over the retina very unevenly. The color-sensitive cones are mainly arranged in the macular region. They achieve their greatest pack-

32 Milestones Innovation 17, Carl Zeiss AG, 2006 Attack on the retina (drusen) lead to a gradual deteriora- AMD and diabetic retinopathy are Left: Color image of a retina tion of vision. closely linked to age. Since the popu- with drusen in the presence of AMD (age-related Retinal diseases are currently the Diabetic retinopathy is the name lation in industrial countries is aging macular degeneration). main causes of blindness in industrial given to pathological changes in the all the time, diagnostics and therapy countries. The main retinal diseases retinal vessels as a consequence of for these diseases constitute a chal- Right: Fluorescein angiogram of the retina are age-related macular degeneration prolonged diabetes. After 20 years of lenge of the highest order for health in the presence of diabetic (AMD) and diabetic retinopathy. suffering from the illness, 80 – 90% policy. retinopathy. AMD is the main cause of an irre- of diabetics are confronted with the versible loss of central vision for peo- onset of changes to their retinas. Diagnosis and follow-up ple over the age of 50. In the case of With diabetic retinopathy, there are the “wet form” of AMD, the abnor- several shades of distinction between The diagnosis and monitoring of reti- mal formation of new blood vessels non-proliferative retinopathy, char- nal diseases is essentially based on (choroidal neovascularization – CNV) acterized by microaneurysms (vessel the qualitative and quantitative eval- leads relatively quickly to a loss of swellings) as well as hemorrhaging, uation of any morphological changes function in the macular region. The and the proliferative form that leads in the retina, i.e. changes in shape, wet form may only account for to the growth of new retinal vessels color or structure. around 10% of all AMD cases, but (neovascularizations). Given that pro- In the simplest scenario, this is it is the cause of roughly 90% of all liferative retinopathy is highly likely to done by means of a direct visual in- cases of blindness resulting from result in a massive loss of sight, treat- spection of the “fundus” or back of AMD. In the case of the “dry form” ment is absolutely essential at this the eye, e.g., using a handheld oph- of AMD, deposits of waste material stage of the disease. thalmoscope.

Milestones Innovation 17, Carl Zeiss AG, 2006 33 Left: OCT cross-sectional However, the documentation and With the OCT method, it is possi- known as panretinal photocoagula- image of a retina with quantitative analysis of the findings ble to obtain high-resolution virtual tion. This involves the obliteration of macular hole. require special imaging instruments. cross-sectional images (tomograms) peripheral areas of the retina no clos- Middle: VISULASTM 532s The main imaging techniques used of the retina (in vivo and totally con- er than 2-3 optic disc diameters from photocoagulation laser. for this purpose are fundus photog- tact-free) which come very close to the center of the macula by applying Right: Stratus OCT optical raphy with a fundus camera, scan- histological cross-sectional images in more than 1000 coagulation spots of coherence tomograph. ning laser ophthalmoscopy (SLO) and terms of their detail to detail and in- roughly 300-500 µm in diameter. The optical coherence tomography (OCT). formation content (“optical biopsy”). first mass-produced photocoagulator The fundus camera enables a true- The optical coherence tomograph for the non-invasive thermal destruc- to-nature reproduction of the fundus, is therefore an ideal complement to tion of retinal tissue was the Xenon which corresponds to the standard two-dimensional fundus photogra- Light Coagulator from Carl Zeiss in image of the retina obtained in oph- phy, enabling a three-dimensional 1957. These days, only laser photo- thalmoscopy. Its versatility makes it evaluation of the fundus. This inno- coagulators are used. an indispensable basic instrument for vative technique, introduced by Carl For dry AMD, which manifests it- any retina specialist. Scanning laser Zeiss in 1996, is regarded as the most self in a gradual loss of central vision ophthalmoscopes usually only supply significant advance in imaging fundus over many years, there is currently no monochrome images. Their strengths, diagnostics in recent years. curative therapy. Attempts are made however, lie in their ability to record to reduce the increasing handicap by the flow dynamics of the retinal vas- Therapy prescribing low vision devices. cular system (fluorescein angiogra- The therapeutic measures in the phy) and in the low light exposure The method of choice in the area case of the more dangerous wet of the patient during image capture. of therapy for diabetic retinopathy is AMD are geared toward obliterating

34 Milestones Innovation 17, Carl Zeiss AG, 2006 the vessels formed under the macula as a result of choroidal neovascu- details larization (CNV) or toward halting or entirely preventing the formation of new vessels. The vessels are obliter- PDT principle ated using photodynamic therapy (PDT). Unlike thermal photocoagula- The basic principle behind PDT tion, this enables the selective de- lies in the triggering of a photo- struction of newly formed vessels be- chemical reaction in a dye (verte- neath the fovea without causing any porfin = photosensitizer) under damage to the photosensitive sensory the influence of radiant energy. layer above. The products of the reaction (free PDT used to be the only therapeu- radicals) then cause the desired tic option for decelerating or halting damage to the vessels. The dye the progressive loss of central vision and radiant energy on their own with wet AMD. Now the first AMD have no effect. Given that the drugs to impede the growth of new dye is configured so that it is abnormal blood vessels are arriving attracted to the inner walls of the on the market. newly formed vessels, these are damaged selectively when laser light is directed onto them. Karl-Heinz Donnerhacke, Jena

Milestones Innovation 17, Carl Zeiss AG, 2006 35 An Insidious Loss of Vision

Glaucoma is a disease of the optic nerve, characterized by an ir- reversible destruction of the retinal ganglion cells and their nerve fibers (axons). This usually slow damage leads to gradual losses in the field of vision, culminating in blindness. Glaucoma is the second most common cause of blindness with a relative share of 17% worldwide.

Difficult diagnosis

The diagnosis of glaucoma is based essentially on the measurement of intraocular pressure (tonometry), the recording and analysis of morphometric data (optic nerve head, retinal nerve fiber layer, chamber angle, corneal thickness), and function tests (measurement of the visual field/ perimetry). The results of these examinations have to be put together like a jigsaw puzzle and a reliable diagnosis can only be made once all the pieces are in place.

Risk factor: intraocular pressure

An increase in intraocular pressure is one of the main risk factors for the development of glaucoma. The pressure can be measured (tonometry) quickly and easily using an air-puff tonometer, for example. For a reliable diagnosis, measuring the pressure alone is not enough, but it is an indispensable step, particularly for checking the success of any therapy, since a reduction in intraocular pressure can halt the disease – at least for a period of time.

36 Milestones Innovation 17, Carl Zeiss AG, 2006 Analysis of the Top left: Coherence optic shape of the optic disc measurement with the Stratus OCT. nerve head Bottom left: Nerve fiber Morphometric changes in the optic layer thickness distribution in the presence of advanced nerve head may be an indication of glaucoma (image captured glaucoma. Disc shape can be record- using the GDxTMVCC ed and analyzed quantitatively using scanning laser polarimeter). fundus photography, laser scanning Right: Humphrey topography or optical coherence to- MatrixTM perimeter for mography. visual field measurement.

Early detection by thickness measurement

The totality of nerve fibers belonging to the ganglion cells forms the retinal nerve fiber layer (RNFL). Evidence of glaucoma-related damage can be obtained by changes in the thickness of the nerve fiber layer. Countless studies have revealed that RNFL losses supply the earliest indication of imminent glaucoma. They occur before structur- al changes to the disc and losses in the visual field. Therefore, considerable im- as well as the die Welch Allyn® fre- tical coherence tomography. The thick- portance is attached to evaluation of quency doubling technology as these ness of the cornea on its own can be the RNFL for early glaucoma detection techniques target specific sub-groups determined quickly and reliably using and follow-up. The layer thickness dis- of ganglion cells that are the first to instruments known as pachymeters. tribution of the RNFL around the optic display functional failure. nerve head can be determined based Glaucoma therapy on cross-sectional coherence tomo- Chamber angle and graphic images or by using scanning central corneal thick- The main objective of all forms of glau- laser polarimetry (SLP). The measuring ness coma therapy is a sustained reduction principle in SLP is based on the layer in intraocular pressure. thickness-dependent birefringence of A flat anterior chamber and there- The method of choice is to adminis- the nerve fiber layer. fore a small chamber angle are the ter medication. Other options include main risk factors for the emergence of minimally invasive laser treatment and Measurement of acute angle-closure glaucoma. Recent finally surgery. the field of vision studies have also shown that an exces- With laser treatment, the desired sively small central corneal thickness is reduction in pressure is achieved by Even though a loss in the visual field an additional risk factor for the devel- lessening the resistance to outflow of only becomes manifest once the dis- opment of glaucoma in the presence aqueous humor under the impact of a ease has reached a more advanced of high intraocular pressure. laser (e.g., with argon laser trabeculo- stage, perimetry is still regarded as All parameters of interest (anterior plasty – ALT or Nd:YAG laser iridotomy) the gold standard in glaucoma diag- chamber depth, chamber angle, cor- or by reducing the production of aque- nostics. The field of vision is usually neal thickness) can be calculated pre- ous humor through targeted tissue measured using standardized auto- cisely using cross-sectional images of obliteration (cyclophotocoagulation). matic perimetry (SAP). the anterior chamber of the eye, which Chances of early detection are of- can be acquired with the aid of optical fered by blue-on-yellow perimetry sectioning, ultrasonic techniques or op- Karl-Heinz Donnerhacke, Jena

Milestones Innovation 17, Carl Zeiss AG, 2006 37 The oldest written record of eye diseases dates back to the year 1500 B.C.: numerous diseases of the eye are referred to in the Ebers Papyrus discovered between the legs of a mummy in the Theban Necropolis in Egypt by the German professor Georg Ebers in 1872. And does the de- scription “rising water in the eye“ – as Albertus Magnus says – refer to cataracts? Julius Hirschberg sees it as likely that the descrip- tion “darkening of the pupil and whitening disease of the eye” also includes cataracts; even Martin Luther, in his Bible translation of the Book of Tobias into German, translated leucoma, i. e. white coloring, as “Star” (the word used for ‘cataract’ in modern German).

The First Eye Operation – Cataract Surgery

What are cataracts? The ancient study of cataracts has prevailed in ancient medicine since its roots in the Alexandrine era. Prior Hippocrates, the operable cataract Medicine began in Ancient Greece to this, different types of opacity was a liquid that had congealed in the with Hippocrates. Yet the Hippocrat- seen in the pupil, which presumably pupil. This development and the im- ics – Hippocrates and his pupils included cataracts, were still grouped portance of the ideas concerning the – could know nothing of a disease together. The Medical Schools of study of cataracts are made particu- that matched the modern concept Alexandria knew of the existence of larly clear by Rufus of Ephesus (1st/2nd of cataracts as they had insuffi- the lens. The usual name given to it century): “Glaucoma and hypochyma cient knowledge of the anatomical for a long time was the “crystalline were regarded by the ancients as one existence of the lens. None of the body”. and the same thing. Later genera- ideas of Democritus, Hippocrates From this point onwards, medi- tions, however, declared that glau- or Aristotle features the lens in the cine went off on the wrong track coma was a complaint affecting the anatomy of the eye. The writings of and did not leave it again around crystalline fluid, which changes from the Hippocratics contain only a few 2000 years later. At that time, the its normal coloring into a watery blue references that would seem to al- lens was regarded as the main or- color, and that hypochyma was an lude to cataracts. The most impor- gan of sight – as the divinum oculi: it effusion of fluid, which (later) coagu- tant of these comes from Hippocra- may become opaque but, because of lates, between the iris and the crys- tes himself, a single word. The list its importance, this problem was re- talline body. All glaucomas are incur- of illnesses and diseases relating to garded as inoperable. However, one able; hypochymas are usually curable, old people in the Aphorisms include particular problem that was operated though not always”. the following: dimness of sight, blu- on by means of a process known as Hypochysis or hypochyma was a ish opacity of the pupil, and dullness cataract couching was seen to be collective term for the great variety of of hearing. The “bluish opacity” is a something quite different. Accord- different pathological changes in the reference to cataracts. ing to the theory on fluids that had region between the cornea, iris and

38 Milestones Innovation 17, Carl Zeiss AG, 2006 “The lens is just an optical medium”

lens. Rufus described the eye and was a work that draws heavily on Ali Ibn Strictly speaking, the word cataract Left: Eye with cataract. the first person to put the lens in its Isar and Galen, in which he says: as a term for the opacity of the lens Middle: Cataract couching correct position. Galen’s anatomy of “The condition is a membrane – like is just as inaccurate as the word glau- in the salon. Copper en- the eye in the 2nd century comes even spot in front of the pupil, which im- coma that has been used since the graving from Lorenz Heister. closer to the reality, although he still pairs sight due to extensive moisture 19th century. Altdorf, 1713, Erlangen- Nuremberg University believed that the lens was the main that gradually penetrates the eye and In 1543, in his extensive work library, Germany. organ of sight. His system, which is coagulates because of the cold”. “humani corporis fabrica”, the physi- based on Hippocrates and the theory The term “cataract” first appeared cian and anatomist Andreas Vesalius Right: Modern surgical microscope – OPMI® on fluids, remained uncontested for as a new term in the Middle Ages. continued with the notion that the pico i. Basic microscope more than ten centuries. In the 7th In their translation of the Greek word lens was located in the middle of the for ophthalmologic exami- century, Paul of Aegina in particular “hypochysis”, the Arabs referred eyeball. In 1583, Felix Platter, official nations and operations. followed in the footsteps of Hippo- to the condition as “Nuzulelma”, doctor to the city of Basel, wrote in crates, his ideas based on the writ- “downflow of water”. To this very his book “de corporis humani struc- ings of Galen. The Arabs translated day, the Arabs call cataracts “the blue tura” one crucially significant sen- his writings about cataracts and cata- water”. It is generally accepted that tence: “The lens is just an optical ract couching. When the Roman Em- the Catharginian monk Constantine medium”. Yet, despite this, clinicians pire collapsed, the Arabs became the the African (1015-1087), one of the continued for the time being to keep custodians of the Greek heritage and most famous pupils of the School of faith with the old ideas. protected the Hippocratic-Galenic Salerno, who in Monte Cassino also The second half of the 17th century medicine from the West. translated the “Ten treatises on the finally brought the required change in It was not until centuries later, in eye” of Abu Zaid Hunain (808-873) thinking. In 1656, the German anato- 1363, that the personal physician into medieval Latin, rendered the mist Werner Rolfinck revealed that to the popes at Avignon, Guy de Arabic expression as “cataracta” (wa- cataracts were the consequence of Chauliac, wrote his Chirurgia Magna, terfall) in his work “Liber de oculis”. lens opacity. In 1682, the renowned

Milestones Innovation 17, Carl Zeiss AG, 2006 39 “I understand real cataracts to be opacified humorem crystallinum and not a layer of skin”

Left: Modern intraocular French ophthalmologist Antoine Mai- lished in 1722, that “I understand re- ract operations since the middle of lens (IOL). tre-Jan observed, when couching the al cataracts to be opacified humorem the last century. Middle: Medieval depiction cataract, that it was not a thickened crystallinum and not a layer of skin”. Cataract couching is apparently of cataract couching by membrane that appeared in the ante- Any final traces of doubt were elimi- first described in Ancient Hindustan Georg Bartisch from the rior chamber but a thick round body, nated by Jacques Daviel in 1753 with in the period around 500 years be- 16th century. the lens. On April 6, 1705 the French his work on operating on cataracts. fore Christ by the legendary Indian Right: Eye with artificial doctor Pierre Brisseau made the same doctor Susruta. The first documented lens implant. observation. Despite the misgivings The cataract operation evidence of cataract couching can be of his teacher Duverney, he present- found in the writings of Chrysippos, ed his findings to the Royal Academy The main operating method for a the Stoic philosopher from Soli, in the of Sciences in Paris on November 12, very long time – from the 5th century 3rd century before the birth of Christ. 1705, after which he lost his position B.C. until the 19th century A.D. – in- Cataract couching was unheard-of in at the academy. volved a technique known as cata- Ancient Egypt and Classical Greece. However, it was now no longer ract couching. This was joined from The first, more or less accurate de- possible to restrain this new thinking. around 1750 until into the 20th cen- scription is attributed to Aulus Cor- Too great was the authority enjoyed tury by extracapsular cataract extrac- nelius Celsus from the 1st century and by the surgeon Maitre-Jan, who in tion. The arrival of the 20th century can be found in the chapter “De ocu- 1707 published his “Tracté des mala- saw more and more surgeons switch- lorum vitiis quae scalpello et manu dies des yeux” and declared that in ing to the technique of intracapsular curantur”. actual fact cataracts were an opacity cataract extraction, which involves Cataract couching involved prick- and hardening of the crystal. Charles the full removal of the lens, i.e. in- ing the sclera temporal with a needle de Saint-Yves also writes in his trea- cluding the lens capsule. Artificial (scleronyxis) and pushing the cata- tise on the diseases of the eye, pub- lenses have been implanted in cataract into the vitreous body (depres-

40 Milestones Innovation 17, Carl Zeiss AG, 2006 sio lentis). Interestingly, the Indians were followed in the 2nd half of the method is particularly associated with practiced a somewhat safer method: 18th century by the itinerant cataract the name Choice. At the end of the they opened up the sclera with a cutters, who applied Daviel’s method. 1970s, the second era of posterior sharp lancet and then introduced a In Halle in 1806, Wilhelm Heinrich chamber lenses began. The so-called blunt instrument to push it down, Buchhorn described cataract couch- „J-loop lens“, first presented by which meant that the risk of injury ing through the cornea, calling it Shearing in 1977, which was fixed was smaller than with the use of just keratonyxis. In the second half of the in place in the ciliary sulcus follow- a sharp needle. Arab physicians even 19th century, extracapsular cataract ing an extracapsular operation, soon seem to have performed suction on extraction finally won the day once found universal appeal. It became the soft forms of cataract. Friedrich Jaeger had introduced the prototype for all subsequent lenses. Particularly impressive are the ac- cataract operation technique of an Of crucial importance to this devel- counts of cataracts by Georg Bartisch upper incision in the cornea. This opment was the phacoemulsification in his eye manual “Augendienst”, triumph was also aided by improve- process introduced by Kelmann in published in Dresden in 1583 [ac- ments in the instruments that were 1970. In the last two decades of the count from the surgeon, patient and used and the local anesthetic that 20th century, the main focus was on assistant], and by the surgeon Lorenz was administered. developing new types of lenses, im- Heister from Frankfurt in 1713. In 1922, Professor Anton Elschnig proving the operating technique and, The extracapsular cataract opera- from Prague declared that in special above all, making it safer. Implanta- tion, in which the lens of the capsule cases the lens could be removed in its tion in the capsular sac replaced sul- is opened, was born in 1745: for entirety, i.e. intracapsular extraction. cus fixation. Of vital importance for the first time ever, Jacques Daviel Within a matter of decades, the int- ensuring a safe capsule implantation removed a cataract through an inci- racapsular cataract operation had be- is the precise opening of the ante- sion in the cornea because blood and come an accepted practice. To avoid rior lens capsule. This only became lens residue had entered the anterior a prolapse of the vitreous humor, possible with the help of the circular chamber as a result of an unsuccess- glycerin was given before the opera- capsulorrhexis technique indicated by ful couching operation. tion and oculopression was later ap- Thomas Neuhann in 1985. The 18th century was also known plied. The removal of the lens was The development of foldable lenses as the age of the oculists, because performed using capsule forceps. To made of silicone and acrylic together cataracts were treated not just by prevent any laceration of the capsule, with small incision surgery were the hospital surgeons but itinerant oc- a suction cup was later used. Finally, real advances made in the 1990s. The ulists as well. One such cataract cryoextraction became the method latest developments include multi- couching oculist of the 18th century of choice. The operation was further focal lenses, toric intraocular lenses was Joseph Hillmer from Vienna. He facilitated by means of the enzymatic to correct astigmatism and the in- traveled across Europe, from Por- zonulolysis introduced by Barraquer. corporation of tiny sensors in the in- tugal to Russia. Frederick the Great traocular lenses (IOL) to continuously appointed him a Professor of Oph- Artificial lenses measure intraocular pressure. thalmology at the Berlin Collegium The story of cataracts will continue Medico-Chirurgicum in 1748. Three Harold Ridley is regarded as the pio- and maybe one day the ophthalmolo- years later, Hillmer was exposed as neer of lens implantation: in 1949, gist‘s dream of refilling a completely a charlatan. Even more well-known, he inserted the first artificial lens as emptied capsular sac with a flexible but likewise of dubious character, a posterior chamber lens in the cap- material, thereby restoring not just was the itinerant “chevalier” John sular bag. 1952 to 1962 is the era sight but also accommodation, will Taylor: on his carriage stood in bold of early anterior chamber lenses. become a reality. letters “Qui dat videre dat vivere”. Then came the Dutchman Cornelius In Leipzig, in 1750, he performed a Binkhorst with his iris clip lens, which cataract operation on both of Johann he first used in 1958, though it took Sebastian Bach‘s eyes, but without around another 15 years for the iris- success. Bach went completely blind supported lens to gain wider appeal. and died four months later. A further development was the me- The same fate befell Georg Frie- dallion lens. Parallel to the iris-sup- Gerhard Holland, History of Medicine drich Handel in London in 1758. He ported lens, experiments were being and Pharmacy Collection, Christian Albrechts University Kiel, Germany too completely lost his sight follow- conducted into further developing Dieter Brocksch, Carl Zeiss AG ing an operation carried out by Tay- implantation in the anterior cham- www.med-hist.uni-kiel.de lor. The itinerant cataract couchers ber. Between 1963 and 1978, this www.snof.org/histoire/histoire.html

Milestones Innovation 17, Carl Zeiss AG, 2006 41 All optical inhomogeneities of the lens of the eye – from opacity through to refractive irregulari- ties – are referred to as cataract. The word “cataract” is of Greek origin and means “waterfall”. It is based on the idea that the cause of the clouding of the lens is a membrane that resembles a waterfall.

When the Lens Becomes Cloudy

The most common form of cataract can be removed by means of a rela- (90%) is the so-called “senile cata- tively uncomplicated surgical proce- ract”. To date, its cause is largely un- dure – the natural lens is replaced by known. Besides age, a whole host of an artificial lens – it is the world’s factors play a role in its development, most common cause of visual impair- including excessive exposure to the ments or blindness, accounting for sun. Visual symptoms of cataract in- approx. 50% of all cases. This is be- clude (to varying degrees) blurred cause, in the countries of the third vision, reduced color perception, loss world, the demand for the surgical of contrast, increased sensitivity to procedure far exceeds the possibilities glare and, in extreme cases, blindness available to perform it. (mature cataract). Although cataract

42 Milestones Innovation 17, Carl Zeiss AG, 2006 Diagnosis and planted. In order to do this, both the refraction are also increasing. There- Left: Lens of the eye preparation for the eye that is to be operated on and the fore, the demands placed on the pre- with cataract. operation partner eye are measured. The refrac- cision of the IOL calculation are also Right: IOLMaster® for tive power is then determined from growing. In addition, this trend is optical biometry. The most important preoperative ex- the measurement data using specific being intensified by the development aminations include the inspection of computation formulas. of new intraocular lenses (bifocal, the anterior segment of the eye using The starting variables for calculat- accommodating IOLs), as a higher a slit lamp and the measurement of ing the IOL are the axial length of the degree of precision is a must for the the eye (biometry). eye, the depth of the anterior cham- use of these modern IOLs. The slit lamp examination allows ber (distance from cornea to the crys- Optical biometry on the basis of the severity and position of the lens talline lens) and the radius of curva- short coherence interferometry fully opacity to be reliably diagnosed. ture of the cornea. meets these increasing demands. However, the patient‘s subjective Determining the refractive power Compared to the previous technique visual problems are the crucial fac- of the IOL is a crucial step for the of measuring the length of the eye tor when it comes to the decision on success of a cataract operation. With using ultrasound (ultrasound biom- whether or not to operate. the growing demands now being etry), optical biometry is performed The aim of biometry is to deter- placed on vision in modern society, without any contact, is approximately mine the refractive power of the in- the requirements relating to the pre- five times more precise and also of- traocular lens (IOL) that is to be im- cision of the desired post-operative fers a large number of other advan-

Milestones Innovation 17, Carl Zeiss AG, 2006 43 tages, with the result that this pro- that the lens can be fixed securely in vasive techniques, require the utmost cedure has now become accepted as the capsular sac. With approximately precision from surgeons and from the gold standard in biometry. 10 million operations each year, cata- the instruments that they use. In or- The first and, as yet, unrivalled ract operations are the most common der to perform the operation and for optical biometry instrument is the surgical procedure in the world. the lens to be implanted successfully, IOLMaster® from Carl Zeiss Meditec. A high level of biostability and the surgical microscope must display outstanding optical quality are the sufficient depth of field, excellent Cataract operation characteristic features of modern, resolution and maximum contrast. foldable, hydrophobic acrylic intra- Integrated slit illumination also makes In a cataract operation, the clouded ocular lenses such as the IOL Hydro- exceptional detail recognition pos- nucleus of the lens is first liquefied max®. They also enable modern, mini- sible and can be used beneficially as using ultrasound and then removed mally invasive operating techniques retro-illumination during the extrac- or “aspirated”, while largely preserv- using small incisions. With special de- tion of the lens. ing the lens capsule (phacoemulsifi- vices such as ready-to-use injectors cation). An artificial lens (IOL = intra- (RTU® injectors), a pre-folded artificial Follow-up treatment, ocular lens) is then inserted in the lens can be implanted through an in- if necessary empty capsular sac. The artificial lens cision just 2.8 or 3.2 mm in diameter. is fitted with radially attached support Surgical procedures in the eye, The main complication following a elements – known as haptics – so particularly the modern, minimally in- successful cataract operation is the

44 Milestones Innovation 17, Carl Zeiss AG, 2006 formation of what is known as a sec- This ultimately leads to the desired beam profile designed for optimum Left: Measurement of the ondary cataract. With a probability of destruction of tissue. The effect focusing and feature a precise aiming axial length of the eye using the IOLMaster®. approximately 30%, the remaining of what is known as laser-induced beam system. posterior part of the capsular sac can photodisruption is restricted to an Middle: Successful secondary become cloudy or “opacify” within area of around 100 µm in diameter. cataract removal (posterior capsulotomy). 3 months to around 1 year after the As a result, the clouded lens capsule operation due to the migration of can be reopened with microsurgical Right: OPMI VISU 210 residual epithelial cells. precision without any damage to the surgical microscope. The problem can be remedied, neighboring structures, in particular however, by means of a quick, non- the intraocular lens itself. invasive and completely pain-free A pulsed Nd-YAG laser is used procedure (known as posterior cap- for laser-induced photodisruption, the sulotomy). This procedure makes use beam of which is projected into the of the physical effect in which, at the observation beam path of a slit lamp. focal point of a pulsed laser, if there To ensure that the secondary cataract is sufficient laser power density, non- membrane can be removed safely linear absorption leads to the forma- and effectively with the least possible tion of a microplasma provided suf- discomfort for the patient, the pho- ficient laser power density is present. todisruption laser should have a laser Karl-Heinz Donnerhacke, Jena

Milestones Innovation 17, Carl Zeiss AG, 2006 45 In Practice

Imagine, for a moment, what it would be like to no longer be able to see very well despite optimally adjusted eyeglasses or contact lenses. Things in your everyday life – reading, handiwork and working on your house – become almost impossible and exhausting. Magnifying visual devices can re- store some of the quality of life and normalcy to people with visal impairments.

Higher Quality of Life –

46 In Practice Innovation 17, Carl Zeiss AG, 2006 Electronic Vision Assistant

Visual aids are optical or optoelec- been specifically designed for mobile tronic instruments and can largely use. details compensate for visual defects. Vari- The user places the handheld cam- ous visual aids, such as magnifiers, era over a text for reading and can magnifying glasses and telescopic then set the magnification according Display glasses glasses, can be used depending on to his or her needs. The possibility of Image source: OLED micro-display the degree of visual impairment and increasing contrast supplements the Resolution: 1.44 million pixels the patient‘s environment. already very good image quality. The True Color/16.7 million colors Optoelectronic reading aids are head-worn camera allows the wearer Field of view: 150 diagonal at 2 met. often utilized for high-level visual to read timetables and street signs Weight: < 100 g impairments. These include CCTVs and recognize faces again. As with Frame: flexible titanium frame which make it possible for people all magnifying visual aids, it is impor- with visual defects to read on their tant to have the largest possible field Operating unit with belt clip own again. of view: the visible image of the Elec- Power supply: battery-powered; The electronic Vision Assistant is tronic Vision Assistant corresponds to network adapter the latest development in optoelec- a television with a 150 cm diagonal Connections: TV/video, computer tronic visual aids. It is a portable de- at a distance of 2 meters. (VGA) vice that delivers high magnification Practical tests on people with high- levels to people with visual defects. grade visual impairments have shown Handheld camera (near) The complete, battery-operated that the system is easy to use and Magnification: 5x - 17x system consists of ergonomically de- enables mobility and independence. Dimensions (L x W x H): 107 x 80 x 54 mm signed display glasses, an operating In the opinion of testers, the system unit designed for low-vision patients, offers optimum imaging quality with Head-worn camera (distance) a handheld camera for up close and a large field of view and a high de- Zoom range: continuous from a head-worn camera for distant ob- gree of wearing comfort. 1.4x to 15x jects. All system components have Auto focus, still shot Dimensions (L x W x H): 60 x 35 x 15 mm

In Practice Innovation 17, Carl Zeiss AG, 2006 47 The Electronic Vision Assistant is the result of several years of research at Carl Zeiss. Carl Zeiss Mobile Optics is responsible for product development. The optical design is patented. The precision optics consist of high-tech plastic materials. The latest micro-display technology (OLED) is integrated into the display glasses and provides a brilliant image. This high-contrast, brilliant display is indispensable for use by low-vision patients. Carl Zeiss Vision GmbH will dis- tribute the Electronic Vision Assistant with ergonomically designed display glasses, handheld camera and control unit beginning in the fall of 2006. A head-worn camera the size of a box of matches will be added to the system in early 2007.

Bettina Egger, Carl Zeiss Mobile Optics GmbH [email protected]

Initial successes The Electronic Vision Assistant is a revelation: this device opens up As someone with a severe visual entirely new perspectives to peo- disability, I have used traditional ple with visual defects when it magnifying glasses for almost 15 comes to mastering everyday years in order to navigate every- work situations or private inter- day situations and when I am ests. And, I can easily and com- away from home. As a result of fortably read timetables, posters my size (141 cm/4 feet 7.5 inches) and notices when I am away from and my desire to travel, I am al- home. ways faced with the problem of The adjustable magnification, trying to read timetables in train the resolution and the script in- stations or at bus stops which are version far exceed the possibilities often too high to read using my of telescopic magnifying glasses. magnifying glasses with a focal Furthermore, the Electronic Vision length of 5 cm. As a tester, I was Assistant is significantly more mo- Display glasses able to intensively contribute to bile and ergonomically designed the development of the Electron- than the equipment at my work- ic Vision Assistant over the last station which includes a 22 inch two years, primarily in everyday monitor and a CCTV. tests. I was very impressed by the development of this multi-functional device. Ulrike Weber, BKK Schott Zeiss

48 In Practice Innovation 17, Carl Zeiss AG, 2006 details

What does visual impairment mean?

Visual impairment is a deteriora- tion of a person’s sight that can be traced to a decrease in visual performance and/or a reduced visual field. This is generally caused by diseased or degenera- tive, age-related changes in the retina.

Classification of different levels: • Visual impairment: visual acuity despite best-possible correction is no more than 0.3 (30% residual visual acuity). • Severe visual impairment: vision of 0.05 (5% remaining visual acuity) or less. • Blindness: this is legally defined as remaining visual acuity of 0.02 (2% remaining visual acuity).

What is the effect of visual impairment? A visual impairment so strongly restricts the life of the affected person that many everyday activities can no longer be spontaneously completed.

Magnifying visual devices pre- scribed and fitted by eye care professionals and adjusted by opticians can provide some relief. To provide low-vision patients with near and far vision again, magnified images must be projected onto intact and functional areas of the retina. Handheld camera Control unit Optical magnifying visual aids Magnifiers, magnifying glasses, Concept bino magnifying glasses, handheld telescopes, telescopic glasses.

In Practice Innovation 17, Carl Zeiss AG, 2006 49 50 In Practice Innovation 17, Carl Zeiss AG, 2006 The engineer and microbiologist Claude Bourguignon has been an internationally recognized expert in the assessment of a wine’s terroir since the late 1980s. The French term terroir describes the interplay of climate, soil type, soil fauna, soil condition, and grape variety in terms of how these affect the specific, distinctive characteristics of a wine. With the Left: Claude Bourguignon aid of analyses performed locally studying soil in the vineyard. and the results of microbiological studies, Bourguignon advises Top: Head-worn loupe from Carl Zeiss. winegrowers all over the world, and farmers too, on the different Bottom f.l.t.r.: aspects of soil preparation, plant- Soil fauna Dicyrtoma saundersi ing density, processing methods, Trombidium holosericeum and choice of grape variety. Orchesella flavescens Pseudoscorpion Eisenia foetida.

Head-worn Loupes Improve Wine Quality

In field analyses, not only the perme- and a head-worn loupe from Carl ability of the soil, its compaction due Zeiss. With the aid of the magnifier to plowing and its erosion are stud- he is able to examine the roots and ied, but also the permeability of the the soil fauna. The make-up of the subsoil, which depends on the rock, fauna provides ample information on aluminum oxides and sand it contains. the condition of the terroir. By using Additional chemical methods are used all these analyses it is possible to im- to characterize the quality of the plement targeted measures that have organic material, water quality, soil a long-term impact on the quality of aeration, and the rock composition. the terroir and, consequently, on the Biological tests include the condition quality of the wine. and depth of the roots and an examination of the different soil fauna. In his field analyses of the soil, Claude www.lams-21.com/index.htm Bourguignon uses both a microscope www.zeiss.de

In Practice Innovation 17, Carl Zeiss AG, 2006 51 Telescopic Eyeglasses and Model Airplanes

One of the focal points of research An electrically driven model plane at the Meteorological Institute of is the ideal measuring platform the University of Munich in Ger- for this purpose because it can be many is unusual wind systems. In used flexibly and repeatedly in recent years Joseph Egger, Head terrain that is otherwise difficult of the Theoretical Meteorology to access. The flying measuring workgroup, has been investigat- platform was used in 2001 during ing valley and plateau winds. To the Lhormar II expedition in order achieve this goal, pressure, tem- to examine the valley wind in the perature and humidity have to be Nepalese Kali Gandaki valley and measured at altitudes of approxi- in 2003 to conduct research into mately 1500 m above the ground. the plateau wind on the Bolivian Altiplano.

52 In Practice Innovation 17, Carl Zeiss AG, 2006 The Kali 1 flying a high measuring rate. Stationary, into a pair of glasses to ensure that Left: Helping the Kali 1 measuring platform ground-based measuring stations and the pilots’ hands were free to control measuring platform get off the ground. pilot balloon ascents supplemented the model plane and observe at the The “Kali 1” model was designed the spectrum of measuring methods same time. For the pilots, handling Center: Kepler-type by the model plane pilot Wolfgang used. the telescopic glasses was a major telescopic eyeglasses. Schäper in 2001 for the Lhomar II ex- After the start, the pilot takes challenge, as the magnification used Right: The entire team pedition and built by the firm Model- control of the plane with a range- clearly changes the visual impressions of the Kali Gandaki expedi- bau Müller in a total of ten models. optimized remote control device. conveyed. The model planes observed tion: scientists, pilots, bearers and kitchen staff Stephan Lämmlein and Philip Kolb He is supported by a colleague who are imaged with a greater size on the in the border area between from the German Aero Club were al- constantly observes the plane with retina and the visual system therefore Nepal and Tibet. so available as pilots. During the en- a pair of binoculars. The pilot him- perceives them as being closer. Move- tire measuring campaign, ten of these self is equipped with a special visual ments inside the field of view are also models, equipped with miniature sys- device, a pair of telescopic eyeglasses greater due to the magnification fac- tems, were used. The model airplane from Carl Zeiss to enable him to also tor. This is why microsurgeons, for with a wingspan of 2.1 meters and a control the plane safely and precisely example, cannot operate with magni- battery-driven electro-drive, weighed at high altitudes. fying visual devices until after a con- 3.1 kilos and reached a height of The telescopic eyeglasses were siderable training period. 2200 meters above ground. Dur- specially produced for the pilots. ing the flight time of approximately They consist of a system with a Ke- 25 minutes, the temperature and pler design and feature 3x magnifi- humidity profiles were measured at cation. The telescope was integrated

In Practice Innovation 17, Carl Zeiss AG, 2006 53 The Kali Gandaki a conclusive explanation was finally details wind system found for the development mecha- nism of the Kali Gandaki winds. A Joseph Egger and his team had set wall separates the Mustang basin Valley of the Kali Gandaki themselves the goal of investigat- from the world in the south. A nar- ing the unusual wind system in the row passage through the wall repre- The valley of the Kali Gandaki features two superlatives: world’s deepest valley together with sents the valley section from Ghasa between Kalopani and Larjung one finds oneself standing the model plane pilots Wolfgang to Marpha. If the sun shines from at the bottom (approx. 2540 meters) of the world’s deepest Schäper, Stephan Lämmlein and Philip above, the air in the basin heats up valley. Its winds display the most extreme diurnal cycle Kolbe. While a wind with storm force strongly, and that in the foreland to a known to scientists. The 8167-meter Dhaulagiri in the west blows into the valley during the day, lesser degree as there is much greater and the 8091-meter Annapurna in the east are only about the wind leaving the valley at night is mass to be heated there. In the gate- 35 kilometers apart at this point. This means one is around weak. way, a valley wind then emerges, the 5500 meters under the mountain peaks. Therefore, this wind system is to- speed of which then increases. This At the breakthrough, the distance between the river bed tally different from the wind systems wind extends into the posterior part and the peaks is more than 5000 meters. The Kali Gandaki observed in large Alpine valleys. The of the basin. In the narrow connect- is one of the four large rivers in Nepal. It rises in Mustang question to be asked was how this ing area, the winds accelerate and on the border with Tibet and flows into the Ganges. unusual wind system can develop in reach the basin in the form of strong At Ghasa, the river rushes downward by a thousand the first place. gusts. meters in a steep canyon and finally approaches Nepal’s By means of very successful meas- lowlands. urements and computer simulations,

54 In Practice Innovation 17, Carl Zeiss AG, 2006 BeBenii Mamore Titicacaseacaseeacase

Copacabana LaL Pazaz

DesaquaderoDesaquaDesaquadero Cochabamba

Oruro

The Altiplano PooposeePoooposee wind system details Sucre Potosi The Altiplano in the Andes is the largest high plateau in the southern The Altiplano AltiplanoAltip o hemisphere. Extensive tablelands in Pilaya the tropics and subtropics display an The Altiplano (Puna, Páramo) is independent diurnal air circulation. a plateau between the high moun- Tarija Due to the strong solar irradiation, tain ranges of the western and Villazon the earth’s surface is strongly heated eastern Andes. The Altiplano lies during the daytime. The hot ground at an average altitude of 3600 m acts like a hot plate under the at- above sea level and extends over mosphere above it. The air above the a surface of about 170,000 km². Altiplano is heated to a considerably Lake Titicaca in the north, Lake greater extent than the surrounding Poopó and the Lago Coipasa in air at the same level above the low- the middle as well as the Salar de land. This results in pressure gradients Uyuni salt lake in the south are the with an area of low pressure above most important stretches of water the plateau and an area of high pres- on the Altiplano. The climate of sure above the lowland. From these the Altiplano is cold and semi-arid gradients of temperature and pres- to arid, and the average annual sure, an extreme wind is produced temperatures fluctuate between from the lowland to the Altiplano. 3 degrees in the western region and 12 degrees at Lake Titicaca.

Top: The deep Kali Gandaki valley channels the winds from Nepal toward the Tibetan plateau.

Center: Philip Kolb navigates with the Zeiss telescopic eyeglasses while Wolfgang Schäper follows the model with a pair of binoculars for added safety.

Right: Initial preparations against the backdrop of the 5916 m-high Licancaburs on the Altiplano.

In Practice Innovation 17, Carl Zeiss AG, 2006 55 Other research terraces. From the meteo-plane „Kali“, ing two Oman expeditions. Schäper‘s projects Schäper developed the photo-plane task was to use the “Horus” photo- “Horus” for the installation of a high plane to map the ecosystems using There were also assignments for the resolution digital camera. About 20 high resolution aerial photos: for the “Kali” and its team in Germany. In flights were conducted during two ex- scientific analysis of the systems on August 2005 the Munich meteorolo- peditions in the spring and fall of the one hand and to record the gists moved close to Neuschwanstein 2005. status quo on the other. The flights, Castle to investigate a wind phenom- most lasting a half an hour, took enon never experienced before. “Horus” place between 1000 and 1400 Flights were also undertaken on the the photo-plane meters above the ground. With about Zugspitze mountain in order to study four flights a day, several thousand the emergence and dynamics of ban- The analysis of changes in the condi- pictures were obtained in all. Schäper ner clouds. tions and processes of agricultural used the special telescopic eyeglasses Andreas Bürkert from the Univer- production in Oman’s oasis settle- from Carl Zeiss to control the plane sity of Kassel approached Wolfgang ments is part of an interdisciplinary, safely and precisely at the high Schäper with a totally different task: in humanistic and scientific project of altitudes. Oman’s Hajar mountains, aerial photos the workgroup “Ecological Crop were to be taken of remote mountain Farming and Research into Agricul- oases. The subject of scientific interest tural Ecosystems in the Tropics and Wolfgang Schäper, ModellFlugGruppe Markdorf www. mfg-markdorf.de here was the mapping of field cultures Subtropics” of University of Kasel in www.wiz.uni-kassel.de/ink/ that were thousands of years old and Germany. In 2005 a specially www.meteo.physik.uni-muenchen.de were primarily created in the form of equipped model plane was used dur- www.zeiss.de

56 In Practice Innovation 17, Carl Zeiss AG, 2006 r ata Q

Suhàr

United Mina al Fahl Matrah Arab Emirates Ibrì Muscat Nizwá Sur

Saudi Arabia Oman details Masirah Duqm Oasis settlements in Oman

The Sultanate of Oman lies on the southern coast of the Arabian peninsula. For centuries, highly Ye men Thamarìt Salàlah advanced agriculture and coastal Raysut fishing were the livelihood of the population of Oman. The country’s agricultural structure started to change with the beginning of commercial oil production and the political opening in the early 1970s.

Top: Aerial photo of the Massirat mountain oasis in Oman.

Center: Wolfgang Schäper with the “Horus” photo- plane in Oman’s Hajar mountains.

Right: On the dune of Al Hawiyah.

In Practice Innovation 17, Carl Zeiss AG, 2006 57 Eye Care in Action

Two-man Teams Provide Info on AMD

Left: June 2, 2006 – Start The eyes of the world were focused early detection. Organized by Eva of the Euro Tandem Tour in Berlin. on Munich on June 9, 2006. To be Luise Köhler, wife of the German more exact, all eyes were turned to- President, the tour was initiated by Right: Short break and wards the Allianz Arena where the the “Pro Retina” low vision associa- strategy discussion for opening game of the 2006 Soccer tion. The cyclists – each tandem con- the next stage of the Euro Tandem Tour. World Cup was held. Hours earlier, sisted of one visually impaired rider and a couple hundred meters away, and one with normal vision – set out blind and severely visually impaired on June 2, 2006, from the Reichstag cyclists met at the Town Hall Square (German Parliament) in Berlin and after 8 one-day stages. The 40 tan- headed south. The group arrived in dem teams and 12 individual rid- Zurich, Switzerland, 12 days later ers from eight European countries after a total of 1500 kilometers and (Belgium, Finland, France, Germany, 11,610 meters in altitude in abso- Hungary, Italy, Luxembourg and lutely perfect weather. They were ac- Switzerland) used the game to draw companied on the way by a bus that attention to their interests: Age-re- provided information on diseases of lated Macular Degeneration, or AMD, the retina and ophthalmology, as well which afflicts approximately 4.5 mil- as free vision tests. l people in Germany. AMD leads to the loss of central vision which makes early detection particularly important. Carl Zeiss Meditec supports the biannual Euro Tandem Tour. It is used to provide the public with informa- www.meditec.zeiss.com tion on AMD and the possibilities of www.zeiss.de

58 Eye Care in Action Innovation 17, Carl Zeiss AG, 2006 Prizes and Awards

The Perfect Lens Material Masthead

Innovation, The Magazine from Carl Zeiss No. 17, September 2006 In June 2006, the physicists Prof. Published by: Dr. Martin Wegener and Prof. Dr. Carl Zeiss AG, Oberkochen Kurt Busch were honored with Corporate Communications Marc Cyrus Vogel. the Carl Zeiss Research Award, Edited by: worth EUR 25,000. At the award Dr. Dieter Brocksch, Carl Zeiss ceremony, Dr. Michael Kaschke, 73446 Oberkochen, Germany the Member of the Carl Zeiss AG Phone +49 (0) 73 64 20- 3408 Fax +49 (0) 73 64 20- 3370 Executive Board responsible for [email protected] research, emphasized the impor- Gudrun Vogel, Carl Zeiss Jena GmbH tance of basic research in the field 07740 Jena, Germany of optics: “Optical technologies Phone +49 (0) 36 41 64- 2770 are now an integral part of our Fax +49 (0) 36 41 64- 2941 [email protected] everyday lives and they lay the foundation for future technolo- Articles in which the author’s name has been given do not necessarily reflect the gies. They also make a consider- opinions of the editors. able contribution to innovations Authors: If no information is given to in medical technology and the life the contrary, they can be contacted via sciences.“ the editors. Refraction in normal water Refraction in “metamaterial water” Authors from Carl Zeiss: [email protected] www.zeiss.de www.zeiss.de Text sources: Kerstin Nössig www.aph.uni-karlsruhe.de/ag/wegener/ (Carl Zeiss Meditec AG), Carl Zeiss AG. index.de.html http://photonics.tfp.uni-karlsruhe.de/ If readers have any inquiries about how the magazine can be obtained or if they wish to change their address (quoting their customer number, if applicable), we would kindly ask them to contact the editor. Both scientists work at the Univer- The contributions made to the theory sity of Karlsruhe, and with their work of light propagation in structured Photo sources: André Korwath, Steve Hopkin (www.stevehopkin.co.uk), they have added decisive momentum materials by Kurt Busch’s research Wikipedia, B.W. Weisskopf to the fields of three-dimensional team and the experimental approach- (www.insecta.ch), www.geocities.jp, photonic crystals and optical meta- es adopted by Prof. Dr. Martin Wege- Iziko Museums of Cape Town, Hans-Wilhelm Grömping materials. Unlike common optical ner’s research group have consider- (www.naturschule.com), materials or “normal” crystals, opti- ably enhanced the possibilities for the Linda Amaral-Zettler, David Patterson cal metamaterials display exceptional production of three-dimensional pho- (microscope.mbl.edu). properties, such as a negative re- tonic crystals. The physical properties If not otherwise specified, the photos fractive index. This has far-reaching of these artificially produced materi- were provided by the authors of the articles, or they are factory or archive consequences for the use of these als are unique: the intention is that photos from Carl Zeiss. materials: “perfect” lenses can be one day they will enable researchers Kurt Busch Design: Corporate Design, produced in which diffraction does to build compact chips that function Carl Zeiss, 73446 Oberkochen, Germany. not limit resolution. This can lead to on the basis of light and can be used Layout and composition: MSW, new lithography techniques for the on the Internet, for example. “Light 73431 Aalen, Germany, www.msw.de. Printed by: C. Maurer, Druck und Verlag, fabrication of computer chips. Artifi- as an information carrier has two at- 73312 Geislingen a. d. Steige, Germany. cial materials functioning on the basis tractive properties: first, photons are English version of the magazine: of light and produced with the aid of almost always much faster than elec- Translation Service (S-KS), Carl Zeiss AG, nanotechnology play a key role in in- trons, and second, two light beams Oberkochen. formation technology: their discovery can penetrate each other without ISSN 1431-8040 often leads to huge advances in tech- mutual disruption”, explained Prof. © 2006, Carl Zeiss AG, Oberkochen. nology within a short time. Dr. Martin Wegener. “This is not pos- Permission for the reproduction of sible with an electrical current, since individual articles and photos only after prior permission has been given by the charge carriers influence each the editors and with the appropriate other and produce short circuits.” reference to the source. Martin Wegener

Prizes and Awards Innovation 17, Carl Zeiss AG, 2006 59 InnovationThe Magazine from Carl Zeiss

Photo on back cover: Image of the iris and fundus of the eye with blood vessels. Right half: iris. Left half: fundus.

Photo taken with the VISUCAMPRO NM fundus camera without the use of mydriatic agents to dilate the pupil.