Word: retinas
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Dates: during 1950-1959
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...standard device long used by eye doctors, is built around a six-volt bulb set in a revolving cylinder. In one side of the cylinder a window is cut to show a flashing light like a miniature lighthouse. The patient looks at the light through opalescent glass. If his retina and brain are getting a normal supply of blood and oxygen, the normal subject should see the flicker effect when the cylinder revolves as fast as 45 times a second. But if the eye's arteries are narrowed, the oxygen-starved retina loses sensitivity: the patient sees a steady...