Development and repair of cataract induced by ultraviolet radiation

The long-term development of lens opacities after short-term exposure to ul traviolet radiation (UVR) was determined. Altogether, 200 Sprague-Dawley ra ts 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 and 32 weeks after exp osure subgroups of 20 rats from each dose group were sacrificed. Both lense s were removed for measurement of intensity of forward scattered light. It was found that exposed lenses scatter light more than their contralaterals and that a higher dose induces more light scattering. After exposure to 5 k J/m(2), the mean difference in scattering remained unchanged between 1 and 32 weeks' latency, but the distribution of the individual differences in sc attering became skew. For several animals, lens opacities induced by 5 kJ/m (2) seemed to decrease during the observation period. Earlier observations in complement to current findings implicate that it is optimal to detect cl ose-to-threshold UVR-induced cataract at 1 week after exposure.