The role of fibroblast inhibitors on corneal healing following photorefractive keratectomy with 193-nanometer excimer laser in rabbits.

Corneal stromal haze has been seen following photorefractive keratectomy with the 193-nanometer excimer laser. Topical antimetabolites aimed at decreasing the haze have been investigated in the rabbit model. We used the VISX 193-nanometer excimer laser to create 6.0-millimeter, -5.00-diopter ablations in 10 Dutch rabbits. Each rabbit was randomized to treatment groups using topical prednisolone acetate, 5-fluorouracil, heparin, prednisolone and heparin, or prednisolone and 5-fluorouracil. Topical agents were instilled twice daily for 2 weeks. Corneal stromal haze developed in all of the eyes. At 2 weeks, there was a significant difference between the degree of haze in the treated eyes and in the untreated controls (P = .02). At 6 weeks, no significant difference remained (P = .07). There were no significant differences in corneal haze among the treatment groups. Thus, all treatments reduced haze at 2 weeks, but the effect was transient, with controls clearing to an equivalent haze by 6 weeks. We conclude that the agents investigated in this rabbit model provided only a transient benefit in reducing corneal haze following excimer laser photoablation.