Reducing peak corneal haze after photorefractive keratectomy in rabbits: Prednisolone acetate 1.00% versus cyclosporine A 0.05%

PURPOSE: To compare the effects of topical cyclosporine A 0.05% (Restasis) with those of prednisolone acetate 1.00% (Pred Forte) on corneal haze after photorefractive keratectomy (PRK). SETTING: Gavin Herbert Eye Institute, University of California, Irvine-Orange, California, USA. DESIGN: Experimental study. METHODS: After -9.00 diopter PRK, 15 rabbits were divided into 3 groups and treated for 4 weeks with prednisolone acetate 1.00% or cyclosporine A 0.05% or neither (control). Corneal haze was measured by in vivo confocal microscopy preoperatively and 2, 4, 6, 8, and 12 weeks postoperatively. At 12 weeks, the corneas were evaluated for collagen organization by ex vivo 2-photon second-harmonic generation and stromal cell density. RESULTS: Corneal haze was significantly less in the prednisolone acetate group than in the cyclosporine and control groups during the first 6 weeks postoperatively (P<.02). At 8 weeks, there was no significant difference between the 3 groups. There was no significant difference in haze between the cyclosporine and control groups at any time. The stroma was also significantly thinner in the prednisolone acetate group than in the other groups for the first 4 weeks postoperatively (P<.02). Second-harmonic generation scar thickness measurements at 12 weeks were not significantly different between the groups, although the prednisolone acetate group tended to have lower stromal cell density. CONCLUSION: Cyclosporine A 0.05% had no effect on wound healing after PRK, while prednisolone acetate 1.00% significantly reduced peak corneal haze but had no effect on long-term corneal haze after discontinuation of the drug.