OPTICAL EFFECTS OF UV-A AND UV-B RADIATION ON THE CULTURED BOVINE LENS

The effects of repeated exposures to UV-A (335 nm) and UV-B (305 nm) r adiation on the crystalline lens were studied by treating cultured bov ine lenses daily or weekly. The effects of irradiation on lens optical quality were monitored using an automated scanning laser system that records both relative transmittance and focal length across the lens. Relatively low radiant exposures of UV-B were used (0.06, 0.03, 0.01 J /cm(2)) compared to UV-A (1.44 J/cm(2)). In total, 38 treated lenses a nd 32 controls were cultured for times ranging from 400-1000 hours. Re sults indicate that this range of UV-B exposure may represent the thre shold for in vitro UV-B induced opacification. Lenses treated weekly w ith 0.06 J/cm(2) UV-B showed a significant decrease in transmittance c ompared to controls 69 hours after the first treatment and an increase in focal length variability. The ability of the lens to repair itself , as found in a previous single dose study, was absent after repeated doses. Lenses exposed daily to 0.03 and 0.01 J/cm(2) UV-B showed no si gnificant change in transmittance or focal length variability compared to controls. Daily exposure to 1.44 J/cm(2) UV-A resulted in no signi ficant change in transmittance or focal length variability compared to controls.