Photosensitization of the eye by 8-methoxypsoralen.

Abstract

The photosensitizing effect of 8-methoxypsoralen in the eyes of laboratory animals was studied utilizing a high intensity grating monochromator as the light source. The action spectrum for this effect was found primarily in the long ultraviolet range with some activity demonstrated also in the mid ultraviolet. The maximum efficiency of long ultraviolet was found between 320 and 340 nm with decreasing efficiency to 330 nm and no effect for wavelengths longer than 380 nm. Guinea pigs were more susceptible to photosensitizing injury with psoralen than were rabbits and experimental data suggests that this is due to a difference in penetration of the 8-MP into the eye. When guinea pigs were given doses of 8-MP comparable to therapeutic doses in man no eye injury was detected.