LONG-TERM DEVELOPMENT OF LENS OPACITIES AFTER EXPOSURE TO ULTRAVIOLET-RADIATION AT 300-NM

The long-term development of lens opacities after short-term exposure to ultraviolet radiation (UVR) was determined. Altogether, 200 Sprague -Dawley rats received unilaterally 5 or 20 kJ/m(2) UVR (lambda(MAX) = 300 nm, lambda(0.5) = 10 nm) in vivo, during 15 min. At 1, 4, 8, 16 an d 32 weeks after exposure subgroups of 20 rats from each dose group we re sacrificed. Both lenses were removed for measurement of intensity o f forward scattered light. It was found that exposed lenses scatter li ght more than their contralaterals and that a higher dose induces more light scattering. After exposure to 5 kJ/m(2), the mean difference in scattering remained unchanged between 1 and 32 weeks' latency, but th e distribution of the individual differences in scattering became skew . For several animals, lens opacities induced by 5 kJ/m(2) seemed to d ecrease during the observation period. Earlier observations in complem ent to current findings implicate that it is optimal to detect close-t o-threshold UVR-induced cataract at 1 week after exposure.