EXCIMER-LASER CORNEAL SURGERY AND FREE OXYGEN RADICALS

Corneal photoablation with 193 nm argon fluoride excimer laser is a ne w technique for the treatment of refractive errors and for removing co rneal opacities and irregularities. Ultraviolet radiation and thermal injury induce free radical formation in the tissues. The aim of this s tudy was to confirm the production of free radicals by excimer laser p hotoablation in rabbits. The thermal changes of the posterior corneal surface were recorded during excimer laser photoablation. The lipid pe roxide (LPO) levels and superoxide dismutase (SOD) activities of aqueo us humour were measured after excimer laser keratectomy. The aqueous L PO levels were not changed after excimer laser ablation, but both the thermal increase in the cornea during the photoablation and the decrea sed aqueous SOD activities suggest that free radicals are formed in th e cornea during excimer laser keratectomy, and that they may be respon sible for some of the complications of excimer laser corneal surgery.