DOCSLIB.ORG

Eye Anatomy Introductory Article

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Eye Anatomy Introductory Article Eye Anatomy Introductory article Thomas C Litzinger, Miami University, Oxford, Ohio, USA Article Contents Katia Del Rio-Tsonis, Miami University, Oxford, Ohio, USA . Introduction . An Overview of the Basic Structures and Functions of the Simple Eye: Human as Primary Model The eye is a small yet multifaceted unit of anatomical machinery in which each structure . The Retina as a Part of the Central Nervous System works in accord with the next, refracting, constricting, dilating and chemically reacting to . Metabolic Support for Photoreceptor Cells from the convert patterns of light into discernible images. Eyes can be divided into two broad Retinal Pigment Epithelium categories: the ‘simple’ eye of vertebrates and the compound eye of invertebrates. Focusing of Light onto the Fovea in Primates . The Compound Eye Introduction . Evolutionary Trends of Eye Structures . Summary The eye has been described by Charles Darwin as both perfect and complex. There are several structural and functional variations that exist between organisms, yet it muscles, the lens possesses the ability to change shape. would be incorrect to say that one is superior to the next. Depending on its form, objects at various distances can be This is the perfection that the eye beholds; each eye has brought into focus. The lens also slightly improves the evolved to suit precisely the necessities of its possessor. already refined image from the cornea, and projects it onto Though numerous and intricate, the many eyes of the the retina. The retina, which literally means ‘net’, catches world can be placed into two very general categories: the light via its photoreceptor and pigment epithelial cells. simple and compound. The photoreceptor cells’ photopigment molecules absorb Though different in appearance, these two models of the the light, causing a change in the photoreceptor’s eye are actually quite similar in their most elementary membrane potential. This initiates a series of signals that functional components. One particularly well-conserved travel through the neurons of the retina, and into the optic molecule between organisms is the light-absorbing protein nerve leading to the brain. This signal is then received and opsin, which essentially initiates the sequence of events processed by the brain as an interpretable image. leading to image formation. Though the most basic visual molecules such as opsin have not been selectively altered in A closer look at the structures involved in the a drastic way by environmental pressures, the anatomical morphology of the eye has. This divergent evolution has entry of light into the eye led to the formation of such dissimilar eyes as that of the The cornea human (simple eye), the fly (compound eye), and many in between. As mentioned, along the path of light into the eye, it will first encounter the cornea, which is a transparent body consisting of an epithelium, a thick fibrous structure made up of connective tissue and extracellular matrix, a An Overview of the Basic Structures and homogeneous elastic lamina and a single layer of endothelial cells. The cornea is the primary contributor Functions of the Simple Eye: Human as in the focusing of light on the retina. Following the basic Primary Model laws of refraction, as incident light encounters a medium possessing a greater refractive index than that of air, Along light’s journey through the eye it is slowed down, propagation slows down, thus bending the beam’s path. bent, absorbed, and converted by various structures The cornea would be an example of such a medium, (Figure 1a). As light approaches the eye it first comes in possessing refracting capabilities. When light hits the contact with the cornea. The cornea refracts the light, surface of the cornea, it slows down and converges towards causing the image to converge on its way to the iris and the centre of the eye, thus reducing the image that has been pupil. Depending on the intensity and availability of the reflected to the eye. Though the cornea bends light, its light, the iris will contract or expand adjusting the pupil transmission is very characteristic of the transparent media size. In situations of low light, the pupil will be larger, that it is, the main characteristic of transparency being the allowing for the passage of enough light to form a minimal scattering of light, and the continuing transmis- discernible image. The opposite is true in situations of sion of light in its original direction, both of which abundant light, for an excess of light results in poor contribute to discernible image formation. These intrinsic imaging as well. Once through the gate of the pupil, the properties of the cornea are made possible by the spatial light is received by the lens. With the aid of auxiliary uniformity of its cells, which contribute to the acuity of ENCYCLOPEDIA OF LIFE SCIENCES / & 2002 Macmillan Publishers Ltd, Nature Publishing Group / www.els.net 1 Eye Anatomy Figure 1 (a) Three-dimensional representation of the structures of the human eye. (b) Cross-section of the human eye, and an enlarged view of the various layers of the retina. light transmission. With these elements present, the cornea structures: the iris and pupil. The two structures work as makes up the first of many critical components of the the regulators of the amount of light passing through the functioning eye. system. The iris is a pigmented sheet of tissue that lies directly in front of the lens, and has the ability to restrict and dilate with the aid of sphincter and dilator muscles, The pupil and iris respectively. This contraction and dilation regulates the The light must cross through the aqueous humour, the aperture of the eye, the pupil. In cases of abundant light, body of fluid that fills the anterior chamber between the the iris lessens the pupillary aperture with the aid of the cornea and the lens, so that it can reach the next group of sphincter muscles, trying to avoid the admittance of too 2 ENCYCLOPEDIA OF LIFE SCIENCES / & 2002 Macmillan Publishers Ltd, Nature Publishing Group / www.els.net Eye Anatomy much light which would eventually result in the processing the human central nervous system that is exposed to stimuli of a muddled blur. The opposite is true when light is from the outside environment. lacking. The pupil becomes greatly dilated in an attempt to gather as many photons as possible for imaging. Organization of the retina into the different The lens cell and synaptic layers Once the correct amount of light has entered the eye The retina can be divided into many distinguishable layers through the pupil, it encounters the lens. The lens, ( ). The first layer to interact with light coming from composed of a lens epithelium layer covering a mass of Figure 1b the lens is the retinal pigment epithelium (RPE) layer. The lens fibres, is primarily made up of proteins called RPE cells do not contribute directly to the transformation crystallins, which further refine the image from the cornea. and transduction of information in the retina, but do Like the cornea, the molecules of the lens are densely provide supportive functions to the photoreceptor cells, packed and uniformly spaced. This is necessary for its which lie just above this layer. The next set of cells, making transparency. The lens has an inherently greater index of up the photoreceptor layer, are the first of three neural cell refraction than that of the cornea, based on its environ- types (photoreceptor, bipolar cells and ganglion cells) that ment needs. Since the lens is surrounded by the fluid of the contribute to the vertical transferring of signals in the aqueous humour and the vitreous humour, which have a retina. This photoreceptor layer consists of the outer and relatively high index of refraction, the index of the lens inner segments of the rods and cones, which receive and must be higher still if it is to focus the image further and transform photons of light. The nuclei of these photo- contribute to the optical system. receptor cells reside in the outer nuclear layer and their Though the lens has an inherent refractive index, it axons and cell terminals in the outer plexiform layer and actually has the ability to change its degree of refraction the outer synaptic layer, respectively. The outer synaptic with the aid of ciliary muscles. When discussing the process layer represents the site where the photoreceptors first of accommodation, the active altering of the shape of the interact with the bipolar cells and other retinal neurons and lens to bring close objects into focus, it would be marks the transition between the ‘outer and inner layers’ of appropriate to start with the ciliary zonule. The ciliary the retina. Like the outer layers, the inner layers can be zonule consists of a series of thin, peripheral ligaments that divided into nuclear and plexiform layers. The inner suspend and hold the lens in place (also known as nuclear layer contains the nuclei of bipolar cells, horizontal suspensory ligaments). These ligaments, or fibres, are cells, and the majority of the amacrine cells. The inner attached to the area of the ciliary muscle called the ciliary nuclear layer is followed by the inner plexiform layer, body. The ciliary body and the zonule fibres work in where vertical communication between the bipolar cells conjunction to alter the focal point of the eye. When the eye and the ganglion cells takes place, thus making up the is in its most relaxed state, it is focusing at distances beyond second synaptic contact layer. The next layer, the ganglion 6 metres (20 feet). In this state, the ciliary muscle is relaxed, cell layer, contains the cell bodies of the ganglion cells.
Load more

Recommended publications
  • Animal Eyes and the Darwinian Theory of the Evolution of the Human
    Animal Eyes We can learn a lot from the wonder of, and the wonder in, animal eyes. Aldo Leopold a pioneer in the conservation movement did. He wrote in Thinking like a Mountain, “We reached the old wolf in time to watch a fierce green fire dying in her eyes. I realized then, and have known ever since, that there was something new to me in those eyes – something known only to her and to the mountain. I was young then, and full of trigger-itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.” For Aldo Leopold, the green fire in the wolf’s eyes symbolized a new way of seeing our place in the world, and with his new insight, he provided a new ethical perspective for the environmental movement. http://vimeo.com/8669977 Light contains information about the environment, and animals without eyes can make use of the information provided by environmental light without forming an image. Euglena, a single-celled organism that did not fit nicely into Carl Linnaeus’ two kingdom system of classification, quite clearly responds to light. Its plant-like nature responds to light by photosynthesizing and its animal- like nature responds to light by moving to and staying in the light. Light causes an increase in the swimming speed, a response known as 165 photokinesis. Light also causes another response in Euglena, known as an accumulation response (phototaxis).
    [Show full text]
  • Lafranca Moth Article.Pdf
    What you may not know about... MScientific classificationoths Kingdom: Animalia Phylum: Arthropoda Class: Insecta Photography and article written by Milena LaFranca order: Lepidoptera [email protected] At roughly 160,000, there are nearly day or nighttime. Butterflies are only above: scales on moth wing, shot at 2x above: SEM image of individual wing scale, 1500x ten times the number of species of known to be diurnal insects and moths of moths have thin butterfly-like of microscopic ridges and bumps moths compared to butterflies, which are mostly nocturnal insects. So if the antennae but they lack the club ends. that reflect light in various angles are in the same order. While most sun is out, it is most likely a butterfly and Moths utilize a wing-coupling that create iridescent coloring. moth species are nocturnal, there are if the moon is out, it is definitely a moth. mechanism that includes two I t i s c o m m o n f o r m o t h w i n g s t o h a v e some that are crepuscular and others A subtler clue in butterfly/moth structures, the retinaculum and patterns that are not in the human that are diurnal. Crepuscular meaning detection is to compare the placement the frenulum. The frenulum is a visible light spectrum. Moths have that they are active during twilight of their wings at rest. Unless warming spine at the base of the hind wing. the ability to see in ultra-violet wave hours. Diurnal themselves, The retinaculum is a loop on the lengths.
    [Show full text]
  • In Vivo Sublayer Analysis of Human Retinal Inner Plexiform Layer Obtained by Visible- Light Optical Coherence Tomography
    bioRxiv preprint doi: https://doi.org/10.1101/2021.01.08.425925; this version posted January 10, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. In Vivo Sublayer Analysis Of Human Retinal Inner Plexiform Layer Obtained By Visible- Light Optical Coherence Tomography Zeinab Ghassabi*1, Roman V. Kuranov*2,3, Mengfei Wu1, Behnam Tayebi1,4, Yuanbo Wang3, Ian Rubinoff2, Xiaorong Liu5, Gadi Wollstein1,6, Joel S. Schuman1,6, Hao F. Zhang2, and Hiroshi Ishikawa1,6 1 Department of Ophthalmology, NYU Langone Health, New York, NY, United States. 2 Department of Biomedical Engineering, Northwestern University, Evanston, IL, United States. 3 Opticent Inc., Evanston, IL, United States. 4 Neuroscience Institute, NYU Langone Health, NY, United States. 5 Department of Biology, University of Virginia, Charlottesville, VA, United States 6 Department of Biomedical Engineering, New York University Tandon School of Engineering, New York, NY, United States Funding: NIH: R01-EY013178, R01EY029121, R01EY026078, R44EY026466 * These authors contributed equally to this work Correspondence author: Dr. Hiroshi Ishikawa, [email protected] bioRxiv preprint doi: https://doi.org/10.1101/2021.01.08.425925; this version posted January 10, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. Purpose: Growing evidence suggests, in glaucoma, the dendritic degeneration of subpopulation of the retinal ganglion cells (RGCs) may precede RGCs soma death. Since different RGCs synapse in different IPL sublayers, visualization of the lamellar structure of the IPL could enable both clinical and fundamental advances in glaucoma understanding and management.
    [Show full text]
  • Action and Perception Are Temporally Coupled by a Common Mechanism That Leads to a Timing Misperception
    The Journal of Neuroscience, January 28, 2015 • 35(4):1493–1504 • 1493 Behavioral/Cognitive Action and Perception Are Temporally Coupled by a Common Mechanism That Leads to a Timing Misperception Elena Pretegiani,1,2 Corina Astefanoaei,3 XPierre M. Daye,1,4 Edmond J. FitzGibbon,1 Dorina-Emilia Creanga,3 Alessandra Rufa,2 and XLance M. Optican1 1Laboratory of Sensorimotor Research, NEI, NIH, DHHS, Bethesda, Maryland, 20892-4435, 2EVA-Laboratory, University of Siena, 53100 Siena, Italy, 3Alexandru Ioan Cuza University, Physics Faculty, 700506 Iasi, Romania, and 4Institut du cerveau et de la moelle´pinie e `re (ICM), INSERM UMRS 975, 75013 Paris, France We move our eyes to explore the world, but visual areas determining where to look next (action) are different from those determining what we are seeing (perception). Whether, or how, action and perception are temporally coordinated is not known. The preparation time course of an action (e.g., a saccade) has been widely studied with the gap/overlap paradigm with temporal asynchronies (TA) between peripheral target onset and fixation point offset (gap, synchronous, or overlap). However, whether the subjects perceive the gap or overlap, and when they perceive it, has not been studied. We adapted the gap/overlap paradigm to study the temporal coupling of action and perception. Human subjects made saccades to targets with different TAs with respect to fixation point offset and reported whether they perceived the stimuli as separated by a gap or overlapped in time. Both saccadic and perceptual report reaction times changed in the same way as a function of TA. The TA dependencies of the time change for action and perception were very similar, suggesting a common neural substrate.
    [Show full text]
  • The Complexity and Origins of the Human Eye: a Brief Study on the Anatomy, Physiology, and Origin of the Eye
    Running Head: THE COMPLEX HUMAN EYE 1 The Complexity and Origins of the Human Eye: A Brief Study on the Anatomy, Physiology, and Origin of the Eye Evan Sebastian A Senior Thesis submitted in partial fulfillment of the requirements for graduation in the Honors Program Liberty University Spring 2010 THE COMPLEX HUMAN EYE 2 Acceptance of Senior Honors Thesis This Senior Honors Thesis is accepted in partial fulfillment of the requirements for graduation from the Honors Program of Liberty University. ______________________________ David A. Titcomb, PT, DPT Thesis Chair ______________________________ David DeWitt, Ph.D. Committee Member ______________________________ Garth McGibbon, M.S. Committee Member ______________________________ Marilyn Gadomski, Ph.D. Assistant Honors Director ______________________________ Date THE COMPLEX HUMAN EYE 3 Abstract The human eye has been the cause of much controversy in regards to its complexity and how the human eye came to be. Through following and discussing the anatomical and physiological functions of the eye, a better understanding of the argument of origins can be seen. The anatomy of the human eye and its many functions are clearly seen, through its complexity. When observing the intricacy of vision and all of the different aspects and connections, it does seem that the human eye is a miracle, no matter its origins. Major biological functions and processes occurring in the retina show the intensity of the eye’s intricacy. After viewing the eye and reviewing its anatomical and physiological domain, arguments regarding its origins are more clearly seen and understood. Evolutionary theory, in terms of Darwin’s thoughts, theorized fossilization of animals, computer simulations of eye evolution, and new research on supposed prior genes occurring in lower life forms leading to human life.
    [Show full text]
  • Cut-And-Assemble Paper Eye Model
    CUT-AND-ASSEMBLE PAPER EYE MODEL Background information: This activity assumes that you have study materials available for your students. However, if you need a quick review of how the eye works, try one of these videos on YouTube. (Just use YouTube’s search feature with these key words.) “Anatomy and Function of the Eye: posted by Raphael Fernandez (2 minutes) “Human Eye” posted by Smart Learning for All (cartoon, 10 minutes) “A Journey Through the Human Eye” posted by Bausch and Lomb (2.5 minutes) “How the Eye Works” posted by AniMed (2.5 minutes) You will need: • copies of the pattern pages printed onto lightweight card stock (vellum bristol is fine, or 65 or 90 pound card stock) • scissors • white glue or good quality glue stick (I always advise against “school glue.”) • clear tape (I use the shiny kind, not the “invisible” kind, as I find the shiny kind more sticky.) • a piece of thin, clear plastic (a transparency [used in copiers] is fine, or a piece of recycled clear packaging as long as it is not too thick-- it should be fairly flimsy and bend very easily) • colored pencils: red for blood vessels and muscle, and brown/blue/green for coloring iris (your choice) (Also, you can use a few other colors for lacrimal gland, optic nerve, if you want to.) • thin permanent marker for a number labels on plastic parts (such as a very thin point Sharpie) Assembly: 1) After copying pattern pages onto card stock, cut out all parts. On the background page that says THE HUMAN EYE, cut away the black rectangles and trim the triangles at the bottom, as shown in picture above.
    [Show full text]
  • Introduction; Environment & Review of Eyes in Different Species
    The Biological Vision System: Introduction; Environment & Review of Eyes in Different Species James T. Fulton https://neuronresearch.net/vision/ Abstract: Keywords: Biological, Human, Vision, phylogeny, vitamin A, Electrolytic Theory of the Neuron, liquid crystal, Activa, anatomy, histology, cytology PROCESSES IN BIOLOGICAL VISION: including, ELECTROCHEMISTRY OF THE NEURON Introduction 1- 1 1 Introduction, Phylogeny & Generic Forms 1 “Vision is the process of discovering from images what is present in the world, and where it is” (Marr, 1985) ***When encountering a citation to a Section number in the following material, the first numeric is a chapter number. All cited chapters can be found at https://neuronresearch.net/vision/document.htm *** 1.1 Introduction While the material in this work is designed for the graduate student undertaking independent study of the vision sensory modality of the biological system, with a certain amount of mathematical sophistication on the part of the reader, the major emphasis is on specific models down to specific circuits used within the neuron. The Chapters are written to stand-alone as much as possible following the block diagram in Section 1.5. However, this requires frequent cross-references to other Chapters as the analyses proceed. The results can be followed by anyone with a college degree in Science. However, to replicate the (photon) Excitation/De-excitation Equation, a background in differential equations and integration-by-parts is required. Some background in semiconductor physics is necessary to understand how the active element within a neuron operates and the unique character of liquid-crystalline water (the backbone of the neural system). The level of sophistication in the animal vision system is quite remarkable.
    [Show full text]
  • The Evolution of Human Intelligence and the Coefficient of Additive Genetic Variance in Human Brain Size ⁎ Geoffrey F
    Intelligence 35 (2007) 97–114 The evolution of human intelligence and the coefficient of additive genetic variance in human brain size ⁎ Geoffrey F. Miller a, , Lars Penke b a University of New Mexico, USA b Institut für Psychologie, Humboldt-Universität zu Berlin, Germany Received 3 November 2005; received in revised form 17 August 2006; accepted 18 August 2006 Available online 12 October 2006 Abstract Most theories of human mental evolution assume that selection favored higher intelligence and larger brains, which should have reduced genetic variance in both. However, adult human intelligence remains highly heritable, and is genetically correlated with brain size. This conflict might be resolved by estimating the coefficient of additive genetic variance (CVA) in human brain size, since CVAs are widely used in evolutionary genetics as indexes of recent selection. Here we calculate for the first time that this CVA is about 7.8, based on data from 19 recent MRI studies of adult human brain size in vivo: 11 studies on brain size means and standard deviations, and 8 studies on brain size heritabilities. This CVA appears lower than that for any other human organ volume or life-history trait, suggesting that the brain has been under strong stabilizing (average-is-better) selection. This result is hard to reconcile with most current theories of human mental evolution, which emphasize directional (more-is-better) selection for higher intelligence and larger brains. Either these theories are all wrong, or CVAs are not as evolutionarily informative as most evolutionary geneticists believe, or, as we suggest, brain size is not a very good index for understanding the evolutionary genetics of human intelligence.
    [Show full text]
  • Vision-In-Arthropoda.Pdf
    Introduction Arthropods possess various kinds of sensory structures which are sensitive to different kinds of stimuli. Arthropods possess simple as well as compound eyes; the latter evolved in Arthropods and are found in no other group of animals. Insects that possess both types of eyes: simple and compound. Photoreceptors: sensitive to light Photoreceptor in Arthropoda 1. Simple Eyes 2. Compound Eyes 1. Simple Eyes in Arthropods - Ocelli The word ocelli are derived from the Latin word ocellus which means little eye. Ocelli are simple eyes which comprise of single lens for collecting and focusing light. Arthropods possess two kinds of ocelli a) Dorsal Ocelli b) Lateral Ocelli (Stemmata) Dorsal Ocellus - Dorsal ocelli are found on the dorsal or front surface of the head of nymphs and adults of several hemimetabolous insects. These are bounded by compound eyes on lateral sides. Dorsal ocelli are not present in those arthropods which lack compound eyes. • Dorsal ocellus has single corneal lens which covers a number of sensory rod- like structures, rhabdome. • The ocellar lens may be curved, for example in bees, locusts and dragonflies; or flat as in cockroaches. • It is sensitive to a wide range of wavelengths and shows quick response to changes in light intensity. • It cannot form an image and is unable to recognize the object. Lateral Ocellus - Stemmata Lateral ocelli, It is also known as stemmata. They are the only eyes in the larvae of holometabolous and certain adult insects such as spring tails, silver fish, fleas and stylops. These are called lateral eyes because they are always present in the lateral region of the head.
    [Show full text]
  • Arteriovenous Dissection in a Living Human
    Vienna, Austria, 1990. Dordrecht, Holland: Klu- Table 2. Ultrasonographic Findings of 25 Well-Documented Patients wer Academic Publishers; 1993:307-311. With Cavitary Melanoma of the Uvea in English Literature 9. Frazier-Byrne S, Green RL. Intraocular tumors. In: Frazier-Byrne S, Green RL, eds. Ultrasound of the Eye and Orbit. 2nd ed. St Louis, Mo: Ultrasonographic Findings Mosby; 2002:115-190. 10. Scott CT, Holland GN, Glasgow BJ. Cavita- Solid % Mass tion in ciliary body melanoma. Am J Ophthalmol. Component Loculation Echoes in Septa in Thickness Occupied 1997;123:269-271. Source Present on USG Cavitation Cavitation by Cavity 11. Cohen PR, Rapini RP. Nevus with cyst: a re- port of 93 cases. Am J Dermatopathol. 1993; Kennedy5 NA NA NA NA NA 15:229-234. NA NA NA NA NA NA NA NA NA NA NA NA NA NA NA Reese6 NA NA NA NA NA Arteriovenous Dissection Zakka et al7 ϩ Unilocular ϩ −NA in a Living Human Eye: Stone and Shapiro4 ϩ Unilocular ϩ −65 ϩ Unilocular ϩ −75 Clinicopathologic − Unilocular ϩ −60 Correlation ϩ Unilocular − − 30 ϩ Multilocular ϩϩ 40 Fledelius et al8 − Unilocular − − 75 Although the visual results after ar- Scott et al10 − Multilocular ϩϩ NA teriovenous dissection (AVD) seem 1,2 Lois et al2 − Unilocular ϩ −79 encouraging, its effectiveness has ϩ Unilocular − − 59 not been proved in a controlled, pro- ϩ Multilocular − ϩ 31 spective clinical trial. The role of sur- ϩ Multilocular ϩϩ 59 gical decompression itself remains ϩ − Unilocular −64 unclear,3 and little is known about − Multilocular ϩϩ 62 ϩ Unilocular ϩ −55 surgically induced nerve fiber de- ϩ Multilocular ϩϩ 38 fects.
    [Show full text]
  • Root Eye Dictionary a "Layman's Explanation" of the Eye and Common Eye Problems
    Welcome! This is the free PDF version of this book. Feel free to share and e-mail it to your friends. If you find this book useful, please support this project by buying the printed version at Amazon.com. Here is the link: http://www.rooteyedictionary.com/printversion Timothy Root, M.D. Root Eye Dictionary A "Layman's Explanation" of the eye and common eye problems Written and Illustrated by Timothy Root, M.D. www.RootEyeDictionary.com 1 Contents: Introduction The Dictionary, A-Z Extra Stuff - Abbreviations - Other Books by Dr. Root 2 Intro 3 INTRODUCTION Greetings and welcome to the Root Eye Dictionary. Inside these pages you will find an alphabetical listing of common eye diseases and visual problems I treat on a day-to-day basis. Ophthalmology is a field riddled with confusing concepts and nomenclature, so I figured a layman's dictionary might help you "decode" the medical jargon. Hopefully, this explanatory approach helps remove some of the mystery behind eye disease. With this book, you should be able to: 1. Look up any eye "diagnosis" you or your family has been given 2. Know why you are getting eye "tests" 3. Look up the ingredients of your eye drops. As you read any particular topic, you will see that some words are underlined. An underlined word means that I've written another entry for that particular topic. You can flip to that section if you'd like further explanation, though I've attempted to make each entry understandable on its own merit. I'm hoping this approach allows you to learn more about the eye without getting bogged down with minutia ..
    [Show full text]
  • Retinal Anatomy and Histology
    1 Q Retinal Anatomy and Histology What is the difference between the retina and the neurosensory retina? 2 Q/A Retinal Anatomy and Histology What is the difference between the retina and the neurosensory retina? While often used interchangeably (including, on occasion, in this slide-set), these are technically not synonyms. The term neurosensory retina refers to the neural lining on the inside of the eye, whereas the term retina refers to this neural lining along with the retinal pigmentthree epithelium words (RPE). 3 A Retinal Anatomy and Histology What is the difference between the retina and the neurosensory retina? While often used interchangeably (including, on occasion, in this slide-set), these are technically not synonyms. The term neurosensory retina refers to the neural lining on the inside of the eye, whereas the term retina refers to this neural lining along with the retinal pigment epithelium (RPE). 4 Q Retinal Anatomy and Histology What is the difference between the retina and the neurosensory retina? While often used interchangeably (including, on occasion, in this slide-set), these are technically not synonyms. The term neurosensory retina refers to the neural lining on the inside of the eye, whereas the term retina refers to this neural lining along with the retinal pigment epithelium (RPE). The neurosensory retina contains three classes of cells—what are they? There are five types of neural elements—what are they? What are the three types of glial cells? The two vascular cell types? --? ----PRs ----Bipolar cells ----Ganglion cells ----Amacrine cells ----Horizontal cells --? ----Müeller cells ----Astrocytes ----Microglia --? ----Endothelial cells ----Pericytes 5 A Retinal Anatomy and Histology What is the difference between the retina and the neurosensory retina? While often used interchangeably (including, on occasion, in this slide-set), these are technically not synonyms.
    [Show full text]