Physiology of the Retina and the Visual Pathway

Light energy is transformed into sight energy largely by complex enzymatic reactions primarily involving the retinal receptors, a group of bio-chemicals, and a complex coding mechanism in the visual pathways and centers. Three dimensional light waves ranging from about 550 to 750 μ in length, with a speed of 186,000 miles per second, after passing through the transparent ocular media strike the posterior retinal layers where they are transformed into sight energy, basically a form of electric energy having a much slower speed. These electrical waves which are potentially information, are coded in the: occipital visual, motor, and association centers; the frontal sensory and motor centers; external geniculate; anterior quadrigemina; pons; and ganglia. These are connected by nerve fibers which are essentially electric wires. Especially the technical phases are clearly and thoroughly discussed by the author. In retinal photochemistry the principle known enzymes are cholinesterase, lactodehydrogenase, and chymotrypsin. The chemicals