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Abstract
A new method for examining and recording features of the eye has been developed. Using holography rather than photography, we obtained, in a single exposure of a cat's eye, a three-dimensional image containing information about the retina as well as all layers along the optical path. Recording a hologram of a living object posed special problems of physical stability necessitating short exposure intervals. With shorter exposure intervals one needs higher levels of retinal illumination to adequately expose the photographic emulsion, and, unless care is exercised, these high levels of light energy may damage the retina. To optimize conditions for the exposure, the emulsion sensitivity was increased and the anesthesized cat was kept motionless. Agfa 10E70 emulsion was employed and special processing used to increase its speed. The light source was a continuous-wave helium-neon laser with an output of 58 mw. Light energy incident on the retina was only 1,200 erg/cm.2, whereas Department of Health, Education, and Welfare (HEW) guidelines place safe exposures between 50,000 and 100,000 erg/cm2.