Biological Applications and Effects of Optical Masers

Evidence that superoxide dismutase (SOD) enhances and catalase (CAT) reduces blue light toxicity in the monkey retina when injected intravenously (i.v) was inconclusive and it is surmized that i.v. injection is ineffective because these large enzymes have a short lifetime in the circulation and cannot penetrate the blood-retinal barrier. Repetitive eye exposures of trained monkeys to the borad spectrum 330-420 nm were terminated in February 1985 after 1,171 daily exposures in one animal and 584 in the other animal. To date, no lenticular anomalies have been noted. Both monkeys are being maintained in good health and examined with the biomicroscope at frequent intervals. Repetitive daily exposures for 21 days of 440, 475 and 533 nm light t the same retinal site n 3 monkeys have shown that photic maculopathy is cumulative on a daily basis, especially for 440 nm light. In one monkey, daily radiant exposures of 2.8 J.cm-2 resulted in the appearance of a lesion on the 20th day. Histologic data are presented for retinal lesions produced by 40 microsecond pulses of 647 nm laser light at a pulse repetition frequency (PRF) of 1600 Hz. Exposures were 10 s in duration at a peak power to the cornea of the monkey eye of 43 nW. The results are unusual in that the photoreceptors above the reinal pigment epithelium (RPE) are completely ablated. Possible mechanisms are discussed. Keywords: Cataracts; Vision.