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

PURPOSE. To establish the in vitro action spectrum for acute UV cataractoge nesis using whole cultured lenses. The recovery pattern of the induced cata ract was also investigated. METHODS. Aseptically dissected porcine lenses were cultured in glass chambe rs. At I week, lenses were exposed to a predetermined UV energy (J/cm(2)) a t 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 wat er-cooled 1000 W, high-pressure xenon lamp. The lamp output was limited usi ng a deionized water filter, a monochromator, and secondary optics. An elec tronic shutter was used to control the exposure time. The median effective dose, ED50 (i.e., UV energy threshold) for each waveband was statistically determined using probit analysis. Irradiated spots (3.06 mm(2)) on the lens es were monitored every 6 to 12 hours up to 48 hours postirradiation for an y 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, a nd 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 whol e cultured tens is established. These data are comparable to published in v itro (with isolated lens epithelial cells) and in vivo action spectra. The recovery pattern appears to be similar to the in vivo situation.