Impact of Age and Sex in Ultraviolet Radiation Cataract in the Rat

The purpose of this study was to determine the influence of age and sex on the development of ultraviolet radiation (UVR) cataract in rats. Current safety limits for lens damage due to UVR do not consider age or sex. Four age groups of Sprague-Dawley rats (3, 6, 17, and 52 weeks) were exposed to 300-nm UVR at either 5 or 8 kJ/m(2), delivered during 15 minutes. The interval between irradiation and cataract assessment was 1 or 8 weeks. Moreover, two groups of 6-week-old male and female rats were exposed to 5 kJ/m(2) UVR, with cataract assessment after 1 week. The severity of cataract was quantified by measurement of forward light-scattering in isolated lenses. The youngest age group showed development of anterior subcapsular, equatorial, and nuclear cataract, whereas the three older groups exhibited the first two types. The two younger age groups had significantly more cataract than the other groups. The degree of cataract increased from 1 to 8 weeks after irradiation. There was no difference in cataract severity between sexes. Young rats are more sensitive to UVR than old rats. Nuclear UVR cataract develops in young rats but not in adult rats. With the chosen waveband and dose, the time for maximum cataract development to occur is longer than 1 week. There is no difference in UVR sensitivity between the sexes.