Topical ultraviolet light-absorbing chromophore protects against experimental photokeratitis

Ultraviolet radiation may play a causative role in a number of human ocular and dermatologic conditions; reduction of environmental UV light exposure may decrease their incidence. We investigated the effects of two different UV light-absorbing chromophores, octyl methoxycinnamate (Parsol-MCX) and butyl methoxydibenzoylmethane (Parsol-1798) on corneal UV light transmittance, and evaluated topically applied Parsol-MCX for its protective effect against experimental UV light-induced keratitis in New Zealand white rabbits. Both Parsol-1789 (UV-A light absorber) and Parsol-MCX (UV-B light absorber) are well tolerated by New Zealand white rabbit eyes. Pretreatment with a single drop of Parsol-MCX reproducibly protected against UV light-induced keratitis, apparently by absorbing greater than 75% of UV-B (peak wavelength, 308 nm) irradiation.