Action spectrum and recovery for in vitro UV-induced cataract using whole lenses.

PURPOSE To establish the in vitro action spectrum for acute UV cataractogenesis using whole cultured lenses. The recovery pattern of the induced cataract was also investigated. METHODS Aseptically dissected porcine lenses were cultured in glass chambers. At 1 week, lenses were exposed to a predetermined UV energy (J/cm(2)) at specific wavebands ranging from 270 to 370 nm at 5- and 10-nm intervals. The UV energy was generated by a PRA integrated arc lamp system using a water-cooled 1000 W, high-pressure xenon lamp. The lamp output was limited using a deionized water filter, a monochromator, and secondary optics. An electronic shutter was used to control the exposure time. The median effective dose, ED(50) (i.e., UV energy threshold) for each waveband was statistically determined using probit analysis. Irradiated spots (3.06 mm(2)) on the lenses were monitored every 6 to 12 hours up to 48 hours postirradiation for any UV-induced opacity with a dissecting microscope and photomicrography. The ED(50)s were plotted against wavelengths to obtain the action spectrum. RESULTS The threshold values for 270, 300, and 365 nm were 0.057, 0.069, and 137.19 J/cm(2), respectively. Permanent UV-induced cataract was obtained at twice the threshold values for UVB and UVA. CONCLUSIONS An action spectrum for in vitro UV-induced cataract using whole cultured lens is established. These data are comparable to published in vitro (with isolated lens epithelial cells) and in vivo action spectra. The recovery pattern appears to be similar to the in vivo situation.