Helga Kolb 1. General characteristics. Todays research on the retina focuses a great deal of attention on neurotransmission between the neurons of the retina. Varous techniques using autoradiography, immunocytochemistry and molecular biology are being used to mark neurons for neurochemicals, their synthesizing enzymes, calcium binding proteins and receptors and transporters of these neurochemicals. …
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What is glaucoma? David Križaj Abstract Glaucoma, a leading cause of blindness in the world, can be challenging to diagnose because symptoms often appear at late stage of the disease, and challenging to treat because of the irreversible loss of retinal neurons. The term encompasses a heterogenous group of diseases that are characterized by altered …
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The Science Behind Myopia Brittany J. Carr and William K. Stell INTRODUCTION Myopia (near-sightedness) is the most common refractive vision disorder in children. It is characterized by blurring of objects viewed at a distance, and is commonly the result of abnormal elongation of the eyeball – which causes the refractive image formed by the cornea …
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Donnell J. Creel Introduction One of the evolutionary characteristics of the mammalian visual system is the increase of binocular overlap of vision as eyes progress from being located on side of the head such as the guinea pig to the frontal position in Haplorrhine primates. Concomitantly as the proportion of temporal retina …
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Donnell J. Creel 1. Introduction Electrophysiological testing of patients with retinal disease began in clinical departments in the late nineteen forties. Under the influence of the Swedish pioneers, Holmgren (1865) and Granit (1933), the electroretinogram was being dissected into component parts and early intraretinal electrode studies were beginning to tell which cells or cell …
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Sam Nona 1. Overview. The visual system of the goldfish has been the subject of intensive studies for over a quarter of a century. It differs from the visual system of most other vertebrates, including mammals, in that it continues to grow by the addition of new neurons throughout much of the animal’s …
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Peter Gouras 1. Introduction. Color vision is an illusion created by the interactions of billions of neurons in our brain. There is no color in the external world; it is created by neural programs and projected onto the outer world we see. It is intimately linked to the perception of form where color …
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Kevin J. Ford and Marla Feller Introduction The mammalian retina has long been a model system for study of development of neural circuits in the CNS because the adult network is well organized into cell-type specific layers, and the anatomy, physiology and function of many of the retinal cell types is well characterized. A …
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Haohua Qian Properties of GABA receptors GABA (g-aminobutyric acid) is the main inhibitory neurotransmitter in the central nervous system. The inhibitory action of GABA is mediated by the receptors present on the cell membrane, and results in a reduction of neuronal excitablity. At least three types of GABA receptors have been characterized. Table 1 summarizes …
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Helga Kolb 1. General characteristics. At every level of the retina there are reciprocal or feed-back loops in the circuitry so that certain neurons can interact laterally within the same layer, vertically from one layer to the other and indeed from the brain to the retina. The intra-layer feed-back loops are typically provided …
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Helga Kolb 1. General characteristics. Over the last few years, psychophysicists, electrophysiologists, geneticists and anatomists have concluded that there is something unique about the short wavelength system compared with the two longer wavelength systems in the visual system. Fig. 1. Cone mosaic in the fovea where the S-wave or blue …
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Helga Kolb 1. General characteristics. The specialized cone pathways of the central fovea of human and monkey retinas have the least convergence and the greatest resolution capabilities of the visual system. This is accomplished by making the connections as “private” as possible and narrowing them to a one to one relationship in the …
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Use/Permissions: For non-commercial, academic purposes, images and content from the chapters portion of Webvision may be used with a non-exclusive rights under a Attribution, Noncommercial 4.0 International (CC BY-NC) Creative Commons license. Cite Webvision, http://webvision.med.utah.edu/ as the source. About the Authors: Dr. Helga Kolb was born and educated in England receiving B.Sc., M.Sc. and Ph.D. …
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Helga Kolb 1. Overview. When an ophthalmologist uses an ophthalmoscope to look into your eye he sees the following view of the retina (Fig. 1). In the center of the retina is the optic nerve, a circular to oval white area measuring about 2 x 1.5 mm across. From the center of the optic nerve …
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1. Size of the retina. 32 mm from ora to ora along the horizontal meridian (Van Buren, 1963; Kolb, unpublished measurements). Area of the human retina is 1094 square mm (Bernstein, personal communication) calculated from the expectations that the average dimension of the human eye is 22 mm from anterior to posterior poles, and …
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