Word: retina
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Dates: during 1950-1959
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...simple optical principle. The burning effect of the bomb's heat on exposed skin diminishes as the square of the distance (twice as far away, it is one-fourth as strong). But the eye is a lens that concentrates heat and light in a spot on the retina. As distances increase, the spot grows smaller but remains as bright. At four miles away, a nuclear fireball 90 feet across forms a brilliant spot on the retina 1/300th of an inch in diameter. This is larger than the fovea centralis, the part of the retina that is used in accurate...
Conventional spectacles, Dr. Feinbloom explained, are simply magnifying glasses with lenses shaped like part of a sphere. No matter how much they magnify, they do not have enough "resolving power" to project a sharp image on the retina (the screen at the back of the eyeball) if the retina is damaged. Most partially sighted patients have retinas like a coarse-grained photographic plate: they can record a sharp image only if they are fitted with a lens of unusually high resolving power...
...show what the doublet glasses can do, Dr. Feinbloom told of a twelve-year-old Ohio girl who was born with part of the retina missing. Her sight was so poor that she could not go to regular schools and was learning Braille. With doublet glasses she breezed through elementary school. She got through high school with honors and now, at 17, is in college taking journalism and working part time as a reporter...
First he tried to put photographic film into an eye near the center of the retina, the point where the lens brings the image naturally to a focus. This did not work; eye fluids ruined the film. So he cut a small hole in the rear of the eyeball and placed in it a disk of film about as big as a pea. When an object was held six inches away, the lens of the eye brought its image to a focus on the film. The aperture of this "camera," he figured, was somewhere between fI.9...
Creer wants to make clear that pigs, sheep and steers do not necessarily see what their eyes "saw" when they were used as cameras. The image on the retina is "assembled" in the brain into a visual image. No one knows what the brain of a pig may make of a comic strip...