Topical diclofenac treatment prior to excimer laser photorefractive keratectomy in rabbits

PURPOSE: This study sought to determine whether pre- and posttreatment with topical diclofenac sodium 0.1% eye drops suppresses corneal inflammation after 193-nanometer excimer laser corneal ablation more effectively than does posttreatment alone. METHODS: Eight rabbits were divided into four groups. Animals in group I were treated with topical diclofenac every half hour for 2 hours prior to photorefractive keratectomy; treatment was continued every hour for 3 hours after the ablation. Group II animals, used as controls, were treated with the diclofenac vehicle according to the same schedule. The third group (III) received diclofenac topically only after the excimer laser ablation. The fourth group (IV) consisted of normal corneas from these same animals. At 3 hours after ablation, prostaglandin E₂ (PGE₂) levels were measured in the corneas and leukocytes were quantified. RESULTS: Treatment with topical diclofenac significantly reduced levels of PGE₂ compared to treatment with the vehicle (p = .024). Presurgical treatment with topical diclofenac did not result in greater suppression of PGE₂ than did posttreatment alone (5.72 ± 0.91 pg/mL versus 5.79 ± 1.29 pg/mL). Similarly, there was a significant inhibition of leukocyte invasion in the diclofenac treated corneas (I vs II: p = .019, III vs II: p = .024), but no statistically significant difference between pretreatment and posttreatment alone groups (I vs III: p = .72). CONCLUSIONS: Topical administration of diclofenac reduces the release of PGE₂ and the migration of polymorphonuclear leukocytes in the rabbit cornea 3 hours after 193-nanometer excimer laser ablation. However, pretreatment of the cornea, starting 2 hours prior to laser surgery, does not seem to offer advantages over postablation treatment in this animal model.