Word: retina
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Dates: during 1960-1969
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...photographic reproductions to get "serious" work for one's serious study. Originals can be bought and rented for very reasonable prices and are amazingly exciting to have. Etchings and engravings by Picasso, Modigliani, Manet, Chagall, etc., original works, can be bought for less than twenty dollars at Retina Gallery, Fabrications, and at Gropper Gallery along Mass. Ave., just to name a few. These are small works and may come at the end of fifty or even a hundred impressions. But they are the right size for small rooms and very satisfying to own. When you own an original piece...
...blood. Its searing but highly localized heat cauterizes capillaries and other blood vessels as they are severed. Like ordinary light, laser beams pass through transparent substances but are absorbed by darker, opaque materials. Thus they flash harmlessly through the cornea and lens of the eyeball to weld a detached retina back into place, or puncture small holes in the retina to ease the pressure of glaucoma. They also penetrate translucent skin to vaporize skin cancers, or tattoos that out-live the patient's enthusiasm for such decoration. Lasers are being used in data pro- cessing to heat tiny, closely...
...effect, incompletely conveyed by photographs, should surprise no ophthalmologist. It is caused by what is known as "retinal bleaching." When the eye gazes fixedly at the disk, the strong white light reflected from its center falls on the retina, causing a chemical substance in the center to temporarily bleach away. This causes local fatigue, and makes the center of the image appear less intense-a kind of blinding. Thus the weaker light from the disk's edge and the shadows beyond are perceived more intensely than the center and appear more vivid...
Hartline and Granit, by contrast, are primarily electro-physiologists who have made important discoveries regarding the nervous responses of vision. Hartline, 63, a professor at New York's Rockefeller University, has traced the patterns of nerve responses after light touches the retina's receptors. Using horseshoe crabs, which have relatively simple eyes, and frogs, he recorded the electrical signals sent out by a single nerve fiber, learned the neural influences of one receptor cell on another. "We listened in," he explains, "on the small traffic signals in the body of the crab...
Along the same lines, Granit, 67, who was a professor of neurophysiology at the Royal Caroline Institute until last spring and is now a visiting professor at Oxford, uncovered clues to how the eye determines color by demonstrating that nerve fibers in the retina are differently sensitive to lights of different wave lengths. However, for all that is known on "what happens between the outside and the inside" of the eye, says Hartline, the current knowledge of vision is "just a beginning. The next step is to know what happens in the visual centers of the brain." Only a beginning...