Don Wong, RBP photography and 13 tutorial

Fundus photography and

Don Wong, RBP Department of Cabrini Health. Care Center New York, New York

About the author—Don Wong, B.A., RBP, is the chief ophthalmic photographer and man- ager of the Department of Ophthalmology, Cabrini Center, 227 East 19th Street, New York, New York 10003. 14 Journal of Ophthalmic Photography Vol. 2, No. 1 August 1979

Fundus photography and fluorescein angiography

CONTENTS

page

I. Photography in ophthalmology and the apparatus ...... 15

II. Anatomy ...... 26

III. The photographic procedure ...... 32

IV. Photography of the external ; photographic artifacts; the patient ...... 37

V. Fluorescein angiography ...... 46

Reprinted with permission from the Journal of the Biological Photographic Association: 44, 105-115, 148-153, and 45 26-30 69-77, and 104-114. © 1976, 1977, Biological Photographic Association, Inc. Don Wong, REP Fundus photography and fluorescein angiography 15

tutorial

Fundus photography and fluorescein angiography

Don Wong, RBP Department of Ophthalmology Cabrini Health Care Center New York, New York Photography in ophthalmology and the apparatus

Photography has progressed con- Since Dr. Zimmer elected to have the The first known successful fundus siderably since the first permanent pho- manufacturer process his pictures, he photograph of a living human eye was tographic record by Niepce in 1826. The experienced a delay of seven months from published in 1886 in the Philadelphia pioneering work of Louis-Jacque Dag- the time the first picture was made until Photographer (June 5, 1886) as well as in uerre and Henry Fox Talbot and others is the paper negative was processed and he the Photographic News (London). The well accounted in other texts (Newhall, was able to see his clinical photos. photograph was taken by W. T. Jackman 1974, and Gernsheim, 1968). The early and J. D. Webster of England. Their ap- growth of photography occurred mainly Fundus illustration and paratus consisted of a small camera at- because of the natural interest in por- photography tached to the head of the patient and an traits. ophthalmoscopic mirror placed at 45° to The professional position enjoyed by Helmholtzs paper "Beschreibung the camera lens, which deflected light the portrait photographer in the mid- Eines Augenspiegels Zur Untersuchung from a source placed near the patients 1880s is understandably strong. Literally Der Netzaut Im. Lebenden Augel," pub- ear. Exposure time was two and a half thousands of studios were established the lished in Berlin in 1851, introduced the minutes. The resultant picture was very world-over to service the demands for ophthalmoscope to the ophthalmologist poor in detail with a large corneal reflex portraits. In 1852, however, photography (Wallace, 1919). Though he included a in the center, which all but obscured ret- found its way into the field of medicine, drawing of the instrument, nothing was inal details. In the following year, 1887, E. Dr. Behrendt of Berlin (Dommasch, 1965) offered which gave the reader any idea of Barr of Buffalo, New York, also obtained photographed orthopedic patients before what he was able to see with his instru- results which he claimed were improved and after treatment. He was the first to ment. The earliest known paper which by the use of orthochromatic plates. publish an article in which photography contained illustrations of the fundus During that same time, still a third phy- of patients was mentioned. Most clinical (Wallace, 1919) was printed in 1853 by A. sician, Dr. Lucien Howe of New York, photography was done in the portrait C. Van Trigt. It was entitled "De Speculo claimed to have made the first photo- studio with the influence of the portrait Oculi". Seven drawings in black and white graphs of the human fundus. This was photographer in clear evidence. The accompanied the article in which the au- reported at the American Ophthalmo- clinical photographs of that era displayed thor describes various eye conditions. logical Society in 1887. His photographs, the patient against opulent, ornate Early papers and discussions by physi- which required a ten-minute exposure backdrops and furnishings. In the late cians indicated that the Helmholtz time, were also poor in detail and had 1800s photographic illustrations began to ophthalmoscope was not of satisfactory corneal reflexes. appear regularly in medical journals. design, resulting in numerous attempts to It was not until 1899 that the first In 1889, Dr. Frederick Zimmer of find something better. reflex-free photographs of the human Rochester, New York, utilized a revolu- The first known attempt at fundus fundus were shown by Dimmer at the tionary camera introduced to the market photography was made by Dr. Henry International Congress. Working with the by George Eastman of Rochester (Corn- Noyes of New York in 1862 (Mann, 1970). Zeiss Company of Jena, an apparatus was well, 1947). The camera was known as the He reported his work at the International constructed which was very large and Number One Kodak Camera and was the Medical Congress of 1884, describing an unwieldy. Exposure times were in the first successful roll-film camera made. apparatus that he made in an attempt to order of four to five seconds, resulting in This camera utilized sensitized paper that photograph the "retinal vessels in the eye blurry pictures due to eye movements. had a capacity of 100 pictures. The cam- of a rabbit." These attempts, as were Three years later, greatly improved re- era was sent to the processing lab with the other early ones, were abandoned due to sults were obtained through the use of a exposed paper enclosed, where it was insurmountable problems, i.e., the very carbon arc illuminating source which al- 1 unloaded in the dark and processed. The slow sensitivity of the photographic ma- lowed the use of exposures of /10 second. camera was then reloaded and returned terials, as well as glaring reflexes off the Additionally, decentration of the objec- to the customer along with the prints. . tive lenses eliminated the corneal reflexes, 16 Journal of Ophthalmic Photography Vol. 2, No. 3 August 1979

making it possible to photograph a larger Nordenson camera appeared in numerous picture studies of the human eye in 1961 area of the fundus. A collection of these hospital clinics and physicians offices were largely unsuccessful due to the high photographs were published in the first throughout the world, and due to its rel- intensities bf light levels required. Pavia atlas of fundus photography in 1907. A ative ease of handling became an impor- (1933) adapted a Zeiss-Nordenson fundus second atlas was published after Dim- tant part of clinical ophthalmology. camera for motion pictures as early as mers death in 1927. These atlases serve It is generally acknowledged by many 1933; in 1957, Chao and Flocks (1958) as landmarks in fundus photography. in ophthalmology (Meyer-Schwickerath, described a method of calculating the It is interesting to note that Dimmer 1968) that the one man most responsible circulation time of a cats by was not alone in his work on an apparatus for convincing physicians the world over , following injection of 1% to perform fundus photography; Dr. W. of the value of the fundus photograph as aqueous Trypan Blue into the internal Thorner and Dr. Wolfe also produced a permanent documentary record as well carotid . One year later, in 1958, fundus photographs. A bitter controversy as a teaching aid was Dr. Arthur J. Bedell (Flocks, Miller and Chas, 1959), they de- arose between Thorner and Dimmer, of Albany, New York. In one of his early scribed their work in "the determination caused by the fact that Thorners photo- papers, published in the New York State of retinal circulation time with the aid of graphs were poorly illuminated and in- Journal of Medicine, (Bedell, 1927) 115 fundus cinephotography." In this work, cluded a bad corneal reflex. He accused original photographs, along with detailed a Kodak 16 mm Cine-Special camera was Dimmer of retouching his photographs. case histories, were presented, which won adapted to the Zeiss-Nordenson camera, Several years later, Thorner constructed Dr. Bedell the Lucien-Howe prize. An and motion pictures were made through the first stereoscopic fundus camera, editorial in that issue urged all physicians a cobalt blue filter at twenty frames per (Thorner, 1909). to "preserve these photographs for ref- second to record the passage of fluorescein Gullstrand, (1910) described a new erence and study." The article included through a cats retina. Super Ansco- method of reflex-free ophthalmoscopy, detailed descriptions of the camera sys- chrome film (ASA 100) was used. Their referred to as central ophthalmoscopy, tem as well as operating procedures. Dr. time recording device was an ingenious which was to become the basis of design Bedell was to continue as the leading ex- paddle six degrees in width and turned by for all later conventional fundus cameras. ponent of fundus photography in the a 30 RPM synchronous motor, causing the Nordenson, working with the Zeiss Com- United States, and later was to claim to paddle to pass across the light path once pany, utilized this principle to develop the have taken over 130 thousand fundus every second. In 1962, this author adapted first practical, commercially available photographs. An Atlas of his work was a 16 mm Rolex camera to the modern fundus camera. He showed examples of published in 1929, Photographs of the Zeiss fundus camera for motion picture pictures made with his early apparatus at Fundus Oculi. studies of the effect of freezing on a cats an International Congress of Ophthal- After the end of World War II, the retina. This was done to determine the mology, which was held in Washington in electronic flash tube was introduced feasibility of applying cryosurgery to 1922. After many modifications, the into the camera system as an illuminat- ophthalmology. Super Anscochrome film camera was introduced to the market in ing source for photography. (ASA 500) was exposed at 12 frames per 1926. This camera utilized a carbon-arc Meyer-Schwickerath and Niesel (Meyer- second by over-loading the focusing illu- illuminating source and an optical system Schwickerath, 1954) in 1953 and Littman mination of the fundus camera. that allowed for continuous viewing up to (1965) in 1955, incorporated the electronic Early motion picture work to record the time of exposure. Later, the camera flash in the modern Zeiss fundus camera. passage of fluorescein dye was successful was modified even further by Hartinger This intense source was an important due to a great deal of customizing of (1936) who replaced the carbon arc with factor which made possible the work of equipment. Norton (Miami), Dollery an electric lamp. In 1936, in collaboration Novotney and Alvis (1961). Their paper, ( London), Oosterhuis and Ammens with Boeghold, Hartinger developed the A Method of Photographing Fluores- (Netherlands) and Wessing and Littmann reflex-free ophthalmoscopic lens with a cence in Circulating Blood in the Human ( Germany) all achieved a good degree of small black dot etched in the middle. This Retina, was published in 1961 and proved success in this medium. Cinematography lens design was also to he incorporated to he a significant contribution, as well as finally gave way to the closed-circuit TV into future fundus cameras. the catalyst for the establishment of flu- camera, which is capable of producing Just before the marketing of Nor- orescein angiography as a clinical diag- pictures of fairly high quality with mini- densons camera, a Dutch ophthalmolo- nostic test procedure in ophthalmology. mal light levels. Some leading institutions gist, Salomonson of Amsterdam, pre- This ability to photograph the circulation have included video taping into their sented a paper at the 1925 American following the injection of fluorescein dye fluorescein angiographic programs, with Medical Association meeting held in At- once again gave the physician goals that a great deal of success. lantic City, New Jersey, in which he de- the existing equipment could not satis- In the century and a half that has scribed his "recording ophthalmoscope." factorily meet. Once again, the illumina- passed since the beginning of photogra- Two optical systems made up this appa- tion was insufficient, the film emulsions phy, numerous inventive individuals have ratus, one for illumination and the other not sensitive enough and the rate of pho- contributed to the development of the for photography. This camera also uti- tography too slow. chemical processes of photography, the lized the carbon arc as a light source and Novotney and. Alvis were not satis- clinical techniques of ophthalmoscopy allowed an exposure time of about 1/10 fied with single-frame photography after and the instrumentation required to second. The camera apparently did not injection of the dye, a method imposed by combine these two into the art of fundus produce the quality results that the Zeiss the existing equipment. They attempted photography. A search through the liter- Nordenson camera did, and therefore, was to develop a technique which would result ature reveals the determination and per- never developed commercially. The in a higher rate of photography. Motion- sistence of the early scientists, who in Don Wong, RBP Fundus photography and fluorescein angiography 17

spite of constant failure still envisioned ultimate success. Many recognized at an early date the value of photographic documentation. This was demonstrated by a physician, Dr. B. Joy Jeffries of Boston, who published an article in the Transactions of the American Ophthal- mological Society of 1869 (Jeffries, 1869). Dr. Jeffries described a case of a young boy seen in consultation who was kicked in the head by a horse, and who eventually lost his vision. The doctor wrote: .. But that which is of special in- terest, and my reason for reporting this case is, that we here have a per- fectly normal fundus oculi entirely destitute of sensation of light, and with transparent media in front of it. From not being able to communi- cate in time with Dr. Noyes of New Figure 1—A cross section of the Zeiss-Nordenson fundus camera. The incident light beam is projected out of the carbon arc housing by means of two prisms, through the camera optical system and into York, who possesses the necessary the inferior portion of the dilated pupil. The reflected beam emerges from the eye through the central skill and apparatus, an opportunity pupil. was lost to achieve a scientific triumph, namely the photographing of the interior of a normal human eye, which I believe has not yet been done." Apparatus

The instruments and devices created by the early workers were truly cumber- some and awkward to work with due to the great limitation imposed upon the scientists by the technology of the times. The very slow film emulsions sensitized primarily to blue forced the use of in- credibly long exposure times (Howes 10 minutes, and Jackson and Websters 21/2 minutes). Dimmers first application of the carbon arc and Gullstrands achieve- ment in central reflex-free ophthalmos- copy paved the way for modern fundus photography. Dr. J. W. Nordensons work with the Carl Zeiss Jena Optical Compa- ny, which spans about fifteen years, re- sulted in a camera of radical design. This instrument, slightly larger than Gull- strands simplified ophthalmoscope and only a fraction of the size of Dimmers apparatus, was to revolutionize fundus photography and establish it as a routine clinical procedure. Because the camera occupied less than two square feet of table space and could be placed on a small table for use, the camera gained great popu- Figure 2—Diagrammatic cross-sections of four modern fundus cameras for comparison larity, and numerous units were pur- to the Zeiss-Nordenson as shown in Figure 1. chased for hospitals and private offices. A diagrammatic section (Figure 1) of the Nordenson camera (Anon., 1936) shows how the small carbon-arc lamp is mounted over the barrel of the fundus 18 Journal of Ophthalmic Photography Vol. 2, No. 1 August 1979

Year 1967 1973 1976 FISBA RECA-1 Jena Retinophot Jena Retinophot Kowa RC-2 Kowa RC-2 Kowa RC-2 Mamiya R-1 Mamiya FR-200 Mamiya FR-200 Fundus Nikon Hand Nikon Retinapan 45 Mamiya FR-300 Noyori Hand Olympus GRC FF H Olympus GRC FF II Cameras Olympus GRC Olympus PRC Olympus PRC O.P.L. Model 56 Topcon J Topcon TRC-J Available Jena Retinophot Topcon TRC-F Topcon TRC-F Zeiss Seimens Topcon TRC-F3 Topcon TRC-F3 Zeiss Seimens Topcon TRC-FE Zeiss Dyonics Topcon TRC-FE3 Zeiss FF II Topcon TRC-FE300 Zeiss FF III Topcon TRC-FE800 Zeiss Siemens Zeiss Dyonics Zeiss FF II Zeiss FF III Donaldson Stereo Clinitex 1000 Pomerantzeff Equator Plus

Figure 3—The fundus cameras available in 1967, 1973, and 1976. in 1976 a small number of man- ufacturers have available several instrument models to keep pace with the changing technology and applications.

camera, and by a system of optics, The current status of instrumenta- ber of firms offering equipment remained projects an incident beam of light onto the tion in the field today consists of con- at seven, yet two were new companies, lower portion of the dilated pupil. The ventional camera systems put onto the replacing two which stopped production. reflected beam exists the eye through the market by seven major companies (Wong, Between these seven firms, eleven dif- central cornea and an inverted image of 1976) as well as a number of specialized ferent table-model camera systems and the retina is formed by the newly-de- systems and instruments designed for three hand fundus cameras were available signed ophthalmoscopic lens within the special purposes. Each unit, however, as well as several sophisticated "special- barrel of the camera. The photographic utilizes the same principles of the Zeiss- ized" systems devised for special-purpose objective is focused on this image and Nordenson camera, with only slight work. Today, in 1976, only six firms are projects it back onto the reflex mirror of variations (Figure 2). Each camera utilizes left in production, yet there are fifteen the photographic camera assembly and up two independent illuminating sources, table-model systems and two hand fundus onto the plane of the crosshairs. The fo- one a low-intensity incandescent bulb for cameras, as well as the Donaldson Stereo cusing lens of the finder magnifies the focusing and composition and the other fundus camera. There are also two wide- i mage by about 5 times for viewing. When a high-intensity electronic flash tube for angle contact lens cameras. One. the the image is critically focused and the exposure. Both sources share the same Clinitex 100° camera, and the other is the field composed, the shutter is released. A optical pathway. Whereas the Nordenson Pomerantzeff Equator-Plus wide-angle gray glass filter, which is situated in the system projected the illuminating beam camera. The following is a brief summary illumination pathway to cut the intensity onto the inferior portion of the cornea of the major units in use today. It is safe of light to tolerable levels for the patient with the image-forming reflected beam to say that all angiographic work being during the photographic session, auto- passing through the more symmetrical done today in North America is primarily matically swings away to allow the full central cornea, the modern cameras gen- being done with the Zeiss system, and intensity of the carbon arc to be projected erally utilize a ring of light surrounding a secondarily, with the Topcon. into the eye for exposure, and the reflex central shadow area. The ring represents mirror is raised to allow a clear pathway the incident beam and passes through The Jena Retinophot back to the film. peripheral cornea superiorly and inferi- The Retinophot is a table-model With the advent of World War II, orly, while the reflected beam travels camera mounted onto a vertical center- production of the Nordenson camera along the pathway through the shadow post, in turn set into a sliding table-top stopped. The Bausch and Lomb Compa- area centrally. A review (Figure 3) of the base. The camera is powered by a so- ny marketed a version of this carbon-arc instruments available and in use today phisticated program unit, which enables fundus camera, but its numbers were compared to those available two years ago one to select the rapid-sequence cycle li mited and no further attempts by (de Kerk, 1973) and those available eight desired. Delay time after injection may be American optical manufacturers to make years ago (Hansell, 1967) demonstrates established by one control that automat- fundus camera equipment have taken the great state of flux that the industry ically initiates photography after zero place. After the end of the war, both Eu- was in. In 1967, seven manufacturers put time. (The photographer activates the ropean and Japanese manufacturers re- on the market six table models and three starting button at the beginning of the sumed production of fundus cameras. hand fundus cameras. In 1973, the num- injection, steps on the foot switch and the Don Wong, RBP Fundus photography and fluorescein angiography 19

program unit takes over, electronically nism. This made it the second camera on very simple to install. One must merely timing the delay time, then commencing the market to be adjustable in the vertical set the voltage selector button at the rapid-sequence photography automati- plane. Production difficulties have taken voltage which is available. The larger of cally.) The rate of photography is preset, this unit off the market, but the company the two power sources for angiography, as are the number of exposures to be made anticipates a modified version in the fu- the TRC-F3, is quite heavy (121 lbs) and in the rapid sequence. The final portion ture. The Nikon hand fundus camera was is mounted on casters. This power pack of the angiographic study is also preset to capable of doing color photography only, requires the use of 200 V, 220 V or 240 V activate the camera at certain intervals providing a 2.5X image in a 30° view. The AC and should have a line installed for its 1 after cessation of the rapid-sequence camera weighs 3 /2 pounds and has a 10 own use. The flash output is a maximum photography (e.g., one picture every two mm working distance to the cornea. of 350 watt-seconds, adjustable over six or four seconds may be made automati- levels, and has a recycling time of 0.3 cally). In this way, the entire angiographic Olympus GRC FFII and PRC seconds. program may be preset, requiring the hand fundus cameras photographer to activate the starting The Olympus GRC II table-model The fundus camera button only at the beginning of the in- fundus camera is not on the American The original Topcon fundus camera jection. The angle of view is 28° and the market, being restricted primarily to the (Figure 4A) is mounted onto a vertical working distance is 8 mm. Japanese consumer. The camera has an center post, which is fixed onto a floating angle of view of 28° and has a working positioning plate, which in turn is set onto Kowa RC-2 fundus camera distance of 70 mm to the cornea. The PRC a small base. The headrest and chinrest This is a very versatile camera, which hand fundus camera is distributed in assembly is permanently fixed into the in the hands of an experienced person is America by the Codman-Mentor Com- patients end of the camera base. This capable of producing excellent fundus pany. The camera body used is the Ol- unit may be placed onto any small table photographs. Current models feature a ympus PEN-F, a half-frame single-lens for use. Since the camera is mounted onto special power supply for angiographic reflex camera enabling one to obtain twice a vertical center post, which has limited work and a motor drive film advance. The the number of pictures on a roll of film transverse movement, the camera is first camera is portable but also utilizes a small than can be obtained with full-frame positioned at the midline of the patients stand to allow for table-top use. Polaroid cameras. The apparatus weighs a little head, then swung to the right or left film packs can also be used. It weighs only less than two pounds and the working towards the eye to be photographed. 2.2 pounds, making it fairly easy to use as distance is 6.7 min. The Topcon camera has a data re- a hand-held camera. Satisfactory anterior cording system which enables one to rec- chamber angle photographs, external eye Topcon fundus cameras ord either consecutive frame numbers or photographs and even deep cavity pic- The Topcon Company first intro- elapsed time in seconds. This is recorded tures (for example, intraoral) may be ob- duced their line of fundus cameras in 1965 on the film adjacent to the picture area. tained with relative ease. The angle of with the Model 1 camera, followed one Additionally, the photographer also has view is 30° and the working distance is a year later with their first angiographic the option of recording either the pa- short 8 mm to the cornea. unit, the Model 2; Their equipment has tients name or identifying number on become increasingly popular on the each frame by writing this data onto a slip Mamiya FR200 and FR300 American market over the past several of paper and inserting it into the appro- fundus cameras years and is found primarily in physicians priate slot on the time data device. The Mamiya Company offers two private offices. In September, 1975, a Two controls are located on the left table-model cameras, the FR200 and completely new camera was introduced at side of the fund us camera body, one is a FR300 cameras, which utilize a mirror the Annual Meeting of the American diopter lens selector button, which allows system to render the images, rather than Academy of Ophthalmology and Otolar- for the selection of lenses of different an aspherical ophthalmoscopic lens. Both yngology. Designated the TRC -FE, diopter strengths for photography. The of these cameras have a full range of ac- TRC-FE3, TRC-FE300 and TRC-FE800, second of these controls is the filter wheel cessories such as tele-extender lenses for these systems bring the total number of on which the excitation filter for angiog- high-magnification pictures, Polaroid cameras offered by the company to raphy is installed. A small knob situated adapter and remote-control foot-switch seven. on top of the camera controls barrier fil- releases. The cameras, however, are pri- ters and other apertures that are generally marily in use in Japan and have not yet The power sources used for f-stop control. Topcon provides come to the American market. The angle The TRC-J is the smallest of the their own BA interference filters as well of view is 30° and the working distance is Topcon power sources that delivers only as a Kodak Wratten filter, no. 15 (yellow), 30 mm. 50 watt-seconds of light energy, thus re- as a barrier filter for angiography. stricting this unit to color fundus pho- Three major changes in the design of Nikon Retinapan 45 and tography. The TRC-F is the smaller of the the fundus camera body give greatly in- Nikon hand fundus cameras two sources designed for angiography creased versatility to the Topcon FRC-FE In 1970, the Nikon Company intro- with a maximum flash output of 300 and TRC-FET instruments. (Figure 4B) duced to the American market the Reti- watt-seconds, adjustable over five stages. The headrest and chin-rest assembly is no napan 45, a table model, which featured It has a recycling time of one second. This longer on the same base on the fundus a radically wider field of view (45°) than power pack utilizes 100 volt AC through camera body, which allows manipulation other cameras in use at the time. It also 240 volts AC which is adjustable via a se- of the camera to subject to a greater de- featured a new pantographic tilt mecha- lector button over six settings, making it gree than before. More importantly, the 20 Journal 01 Ophthalmic Photography Vol. 2, No, 1 August 1979

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Figure 4A—The Topcon fundus camera, TRC-F. B—The Topcon TRC-FET.

pivotal point of the camera body was film advance and cocking of the shutter less time consuming than leaning off to taken off the vertical center post and for the next exposure. The device is not the side of the camera. moved to a point forward of the ophthal- capable of providing continuous photog- Two Polaroid systems are available, moscopic lens, enabling a lateral swing of raphy, but is used for single-frame pho- the Polaroid attachment Type I, which is the optical head up to 30° with an unin- tography. The motor drive, however, is a simply attached to the 35mm camera terrupted view. On the TRC-FET model, completely automatic device that permits body piggyback-style after the hinged a tilt mechanism is now featured, per- continuous sequential photography as back is removed. The new attachment, mitting a vertical displacement of the long as the trigger is depressed. Type II, is mounted directly to the hack camera of 15° from zero, making periph- The power generators available for of the fundus camera. This adaptor uses eral photography of the superior and in- these new model cameras are the 300 and only 40 mm of a single sheet of film, which ferior fundus a great deal simpler. The 800 series. Both feature an automatic in- means that two images may be made trigger release for photography is on the jector; the 300 series delivers 300 watt- side-by-side on a single sheet of Polaroid joy-stick, giving great convenience in the seconds of light and has a recycling time film type 107 or type 108. photographic sessions. for 3 flashes per second, while the 800 se- All viewing and composing is done ries, delivering the same light output, The Zeiss fundus camera through the eyepiece of the 35 mm camera recycles for 8 flashes per second. system body that is used. The body used on the The Zeiss Company is the pioneer Accessories early systems (TRC-J, TRC-F, TRC-F3) firm in fundus photography, and since the is the excellent Topcon M single-lens re- A fairly wide range of accessories is creation of the Zeiss-Nordenson camera, flex camera equipped with an electronic available for the Topcon system, includ- the company has been the moving force in motor. The camera is also used manually ing a 1.8X magnifying extension tube and the field. Their instrumentation is not for single-frame color photography. a stereo attachment that fits over the only well-known in fundus photography, The camera bodies provided with the front of the camera. There is also the but in other areas of ophthalmic photog- new system (TRC-FE, TRC-FET) are the sighting mirror attachment. This is a raphy as well. Thus, in the early 1960s, type AM and AM-FL single-lens reflex prism that is slipped over the front lens recognizing the potential significance of cameras. These are operated manually, barrel and allows the photographer to fluorescein angiography, Zeiss produced with an Autowinder, or with a motor drive look over the top of the fund us camera at their first angiographic unit, which came system. The Autowinder is an electronic the prism to determine whether or not the to the American market in 1966. Called drive used to control such the operations alignment of the camera to the eye is still the Automatic Fluorescein Angiographic of the body as shutter release, automatic correct. This is considerably easier and Fundus Camera System, it utilized a 35 Don Wong, RBP Fundus photography and fluorescein angiography 21

mm Robot automatic camera body com- down without losing its original alignment bined with a very large power generator, within the dilated pupil. These features the Siemens power pack. are most important during serial angiog- Within a years time, this system was raphy when small adjustments are re- to undergo the first of many modifica- quired to follow a drifting eye in order to tions, and subsequently, the company has maintain optimum camera position marketed four major systems, each with without interruption of photography. The a host of different optical parts as well as ability of the instrument to be positioned different camera bodies, eyepiece directly in front of the eye to be photo- assemblies and accessories. This makes graphed, combined with the swing and tilt the Zeiss system the must versatile, com- movements of the camera, give this sys- plex system on the market. tem maximum versatility and a great ad- It is possible to see numerous varia- vantage over other units. A built-in fixa- tions of the apparatus in use, depending tion device originally intended to be used upon the particular component parts to demonstrate eccentric fixation is lo- utilized, which means that a photographer cated on the front of the fund us camera may need to go through a brief period of body, and may be used to great advantage orientation as he goes from one lab to for patients who cannot see the target another. light with the fellow eye. On the FF III For discussion purposes, the camera fundus camera, a filter slot is situated on system may be divided into the following the side of the instrument, which enables components: the fund us camera (less the one to easily insert filters for photogra- eyepiece assembly); the eyepiece assem- phy: bly, of which there are four; the 35 mm The camera tables have two elevating camera body; and the power generator and lowering controls. One located be- system, from which each model derives its neath the table elevates and lowers the name. entire apparatus for the patients height. Shortly after the introduction of the The second is a flat white knob located in automatic angiographic camera system in the middle of the table top just forward of 1966, Zeiss, in conjunction with a com- the joystick. This control raises or lowers mercial firm known as Ule (later, Dyon- the camera only, and is independent of ics), marketed a unit known as the the headrest and chinrest assembly, en- Dyonics CineFlash, capable of very abling one to change the height of the high-speed photography, and requiring a camera in relation to the eye to follow liquid refrigerant to cool the unit. All slight eye movements in the vertical subsequent modifications in design were plane. The headrest and chinrest assem- done by the Zeiss Company itself. These bly is manueverable by means of a units were the Fundus Flash II (FF II), knurled knob located to the photogra- the Power Pack 260 and most currently phers left, just under the table. This knob the Fundus Flash III (FF III). is used for gross adjustments of the pa- tient-to-camera distance. The fundus camera Optically, the system is superb, with Unlike other models, which are fixed a wide range of accessory lenses to provide onto a permanent base, the Zeiss fundus ample coverage for critical focus on the camera is mounted onto a base which can hyperopic eye as well as on the myopic glide over a table surface on rollers in a eye. Additionally, an astigmatic correction transverse manner, enabling one to posi- control is situated at the top of the fundus tion the apparatus directly in front of the camera body. eye being photographed. The camera is mounted onto this base by a vertical col- Eyepiece assemblies umn situated at a critical point in front of Unlike other units, the Zeiss fundus the instrument, which enables the camera cameras eyepiece assembly is a complete to he swung from right to left without independent system (Figure 5) which may losing its alignment within the dilated be removed from the fundus camera body pupil. It is therefore possible for one to and which has numerous combinations of take a series of pictures in quick succes- fittings for 35 mm camera bodies. Four sion merely by swinging the camera first different eyepiece assemblies are in use to the temporal then to the nasal side of today, the oldest of which was utilized on the first view photograph. The camera the automatic fluorescein angiographic position may also be altered in the vertical camera. This system was soon replaced by plane by a tilting mechanism, which en- a more versatile one, which appeared on ables the apparatus to be tilted up or the FF II fundus camera. 22 Journal of Ophthalmic Photography Vol. 2, No. 1 August 1979

A

C D

Figure 5The Zeiss Eyepiece Assemblies. AAutomatic Robot eyepiece. BFF II with Databox and motorized Pentax camera body. CPrism eyepiece head. DSolenoid mirror eyepiece. Don Wong, RBP Fundus photography and fluorescein angiography 23

A digital time-recording device was it barely comes into contact with the Nikon and Pentax had the added versa- included on the FF II model, replacing the shutter release button of the camera body. tility of a 250-exposure film chamber. sweeping-second-hand clock utilized by The photographer should make several the Robot camera. For single-frame pho- test moves to confirm that the plug is in Power generator tography, exposures are made by de- contact with the shutter release button as The Siemens power generator (Fig- pressing a black lever arm in which two the mirror hits the damper, then he ure 6, page 114) requires 220 volts AC for white plastic plugs are inserted. The should tighten the retaining screw. It is operation, and it is recommended that a mirror in the eyepiece is attached to this advisable thereafter to check these ad- separate electrical line be installed for this lever so that as the arm is depressed, the justments periodically to prevent loss of unit alone. One must be careful in the mirror also is, and is dropped out of the pictures due to the cut-off of the image by combination of settings used with this photographic pathway to allow the light the mirror. pack to prevent overloading with the hack to the film. At the instant the mirror surge of input power, which might cause drops, the eyepiece is blacked out. As the Prism assembly the circuit breakers to shut down the arm continues downward, the plastic Recently, Zeiss marketed an eyepiece system. If the circuit breakers do shut plugs come into contact with the shutter assembly that utilizes a set of prisms in- down, it usually occurs during a serial run, release button of the 35 mm camera body, stead of moving mirrors, thus eliminating causing the electronic flash tube to ignite and slight further pressure downwards the lever arm and a moving part in that and remain very brightly lit for a second the shutter for the exposure. The second assembly. In this way, the problems at- or so (accompanied by a humming sound), white plug at the end of this lever makes tendant with the use of the plastic plugs all of which is followed by a loud snap as contact with the shutter release button of to activate the camera shutter are also the circuit breakers switch off. Photog- the camera body when the 2X magnifying eliminated. Exposures are made by de- raphy may be resumed after resetting the lens is in place for photography. pressing the shutter release button of the circuit breakers, which are situated on the After a period of constant usage, a camera body directly. The photographer lower right-hand corner of the genera- common occurrence that one encounters must adjust to the use of this assembly, tor. is slippage of the white plastic plugs away especially during angiography, because The Dyonics Cineflash power from the optimum positions, causing a some of the light reflected out of the pa- supplies (models No. 708, No. 730 and No. variety of photographic artifacts to ap- tient's eye is diverted up into the eyepiece 760) were developed by the Ule Corpora- pear. If the plugs are too high, greater- and into the photographer's eye. This will tion (later Dyonics) of Woburn, Massa- than-normal pressure must be exerted cause him to lose his dark adaptation. chusetts to be used in conjunction with onto the arm in order to get the plug to the Zeiss Fundus camera. They were reach the shutter release button of the Mirror assembly especially adapted for very high-speed camera body, causing the mirror to hit the The fourth eyepiece assembly in- photography with a maximum of 60 damper at the base of the eyepiece as- corporates a mirror which is solenoid- frames per second. These units are quite sembly with excessive force and to bounce activated and is powered by the power complex, having automatic built-in de- back upwards into the photographic generator. The use of the solenoid elimi- layed timing devices as well as an auto- pathway. If the plugs have slipped too far nates the need for the lever arm mecha- matically controlled photography rate. down, the shutter release button of the nism while still retaining the moving Control outlets on the Cineflash are camera body is activated prematurely, mirror which blacks out the eyepiece at available for numerous accessories. These and the photograph is made while the the moment of photography. This pre- power supplies are capable of such high- mirror is still on its way down. Both these serves the photographer's dark adapta- speed recycling without overheating due conditions result in photographs with the tion. to a liquid coolant system. The Dyonics mirror of the eyepiece assembly intruding A number of 35 mm camera bodies line includes eyepiece assemblies adapted into the photographic pathway, and one are in use today with these assemblies, for motorized Nikons (4 frames per sec- must be able to recognize the malfunction each requiring the appropriate adapter ond) as well as for 35 mm Arriflex motion in order to take the proper corrective ring. Zeiss' own Special ikon body was the picture cameras and camera systems steps. work-horse of single frame color photog- (Vidicon High Speed or Image Orthocon). One clue that is helpful is that on raphy, and some institutions even per- The models No. 708 and No. 730 both those pictures in which the mirror hits the formed their with these have only one flash output (200 watt- damper and bounces upwards, the shad- bodies by depressing the lever for expo- seconds), whereas the No. 760 has two ow of the mirror in the picture area at 6 sure and advancing the film and cocking (100 watt-seconds and 200 watt-seconds). o'clock is often accompanied by a half- the shutter manually. The motorized Neutral density filters control the expo- moon crescent of light at the 12 o'clock Nikon F camera body was adapted at a sure for color photography. position. The photographer may correct very early stage of instrumentation for The Fundus Flash H (FF II) power this misalignment by loosening the small angiography by the Dyonics Company, generator is physically the largest of Zeiss' retaining screws holding the plugs in place enabling rapid-sequence photography to power sources, utilizing 115 volts AC, has and resetting the position of the plug. In be performed at the rate of 4 frames per only three levels of flash output, which are order to do this correctly, he must press second. Soon afterwards, the motorized designated low, medium and high. One the lever down gently until he hears the Leica replaced the Nikon system on the does have the option of installing a mirror tap against the damper. Repeated FF II fundus camera, and finally, the Booster Unit onto the original. FF movements will confirm that position. motorized Honeywell Pentax Spotmatic power pack, giving a maximum of 240 Holding the lever in that position, the II replaced the Leica on the FF III. Each watt-seconds. The booster is operational photographer must adjust the plug until system proved to be quite reliable but the only when the flash output selector switch 24 Journal of Ophthalmic Photography Vol. 2, No. 1 August 1979

struments into this one power generator. A selector switch marked "System 1" and "System 2" diverts the electrical power from one apparatus to the other so that it is possible to utilize this one power source to service two instruments (either two fundus cameras, or a fundus camera and an angiographic unit though not at the same time).

Accessories A number of accessories are available which serve to enhance the results ob- tained. A 2X magnifying lens may be in- serted between the 35 mm camera body and the back of the fundus camera to ob- tain high-magnification fundus photo- graphs; the Allen Stereo Separator, at- tached over the front barrel of the fundus camera automatically yields stereo fundus photos; and a Polaroid film back permits the use of Polaroid film for instant re- sults. Finally, the Zeiss Company, in con- junction with the Urban Engineering Company of Burbank, California, has developed the Zeiss-Urban Retinal Image Display System, which is a video system and which may be mounted onto the camera in place of the regular eyepiece assembly. This permits one to record an- giography onto videotape cassettes. Specialized systems In addition to the conventional sys- tems discussed, a number of customized units as well as specialized units have evolved. Generally, the customized units have been converted by the consumer in order to adapt it to highly specialized projects, and therefore have limited ap- Figure 6—Zeiss Power generators. A—Siemens Power Pack. BDyonics Power Pack. C--FF II. plications. Several other cameras that are DPower Pack 260. EFF III. discussed in this section are commercially marketed, and are systems of radical de- sign and deserve some note. is set on the "high" position. The circuit control foot switch or a stereo photogra- Donaldson stereo fundus camera. breaker, situated at the back of the gen- phy device. All photography and angiog- Previously, most stereo fundus photo- erator is fused for 20 amps. In the event raphy must he performed manually. (A graphs have been obtained by taking two the surge of power during the serial angi- motorized Pentax camera may be used, consecutive pictures which were ulti- ography causes the circuit breaker to shut but an additional DC power source must mately matched together for viewing. down, one merely has to reset the breaker be utilized to activate the camera.) Many technical factors exist which often and resume photography at a slower rate. The Fundus Flash Ill (FF III) has caused difficulty, rendering the two pic- It is advisable to install an electrical line evolved from all previous systems and tures ineffective for a good stereo effect. to service only this apparatus. encompasses some of the best features of The ideal method of producing such pic- The Power Supply 260 is physically each. It is small in size, yet has a good tures is to expose both frames of the stereo the smallest of Zeiss power sources for delivery of light (maximum output 350 pair simultaneously. Dr. David Donaldson angiography. Its recycling capabilities are watt-seconds); it has built-in outlets for of the Harvard Medical School, observing not as fast as the larger units are, yet it is the stereo adapter and motorized drive for the lack of such equipment, undertook to perfectly suitable for clinical angiography. the camera; it has a rheostat for the fixa- "design and make such a fundus cam- This power pack has no provision for tion light intensity; it has foot switch era." motorized rapid-sequence photography control for a focusing light overload; and Based upon the principle of indirect or other accessories such as a a remote- it has the capability to connect two in- ophthalmoscopy as reported by Donald- Don Wang, RBP Fundus photography and fluorescein angiography 25

son (1964), the image of the fundus is split into different pathways by a "field" lens, which in turn re-images it into the film plane. Focusing is done through a binoc- ular eyepiece system. The illumination is provided by two "end-on" electronic flash tubes designed specifically for the camera by Dr. Harold Edgerton of Masschusetts Institute of Technology. These tubes also provide the focusing and viewing illumi- nation by flashing 60 times per second (at low intensity) and then discharging at maximum output for the exposure. The camera is placed on a standard Zeiss table for operation. Clinitex loo n contact lens fundus camera. Marketed by the Clinitex Com- pany of Danvers, Massachusetts, this camera produces a wide-angle view of the fundus by employing a contact lens as its front element. The photographic proce- dure therefore requires that the camera be in constant contact with patients cornea. This 100° view is considerably greater than the 30° view of the conventional systems (Figure 7A). Pomerantzeff Equator-Plus contact lens fundus camera. This is a second wide-angle contact lens camera that was shown for the first time at the American Academy of Ophthalmology and Otolar- yngology (AA00) Meeting in September of 1975. The camera produces a picture with a 150° field of view. It was produced primarily for black-and-white and color pictures of the fundus and will have lim- ited angiographic capability. (Figure 7B) Multispectral fundus camera. Of the customized units in use today, this is probably the most sophisticated, not only in design, but in application. The camera was converted for use at the Applied Physics Laboratory of Johns Hopkins University to study the relative resis- tances to blood flow in the choroidal and retinal vasculatures at very high intra- ocular pressures. This camera performs infrared absorption angiography with the use of intravenous indocyanine green (ICG) dye (Flower, 1972). This dye, in a mixture with sodium fluorescein also permits simultaneous infrared-absorption studies of the choroidal vasculature as well as fluorescein angiographic studies of the retinal vasculature (Figure 7C).

Figure 7Special fundus photography systems. A—Clinitex CA-2 100 contact lens fundus camera. B—Pomerantzeff Equator-Plus contact lens fundus camera. C—Multispectral fundus camera.