Effect of Topical Phenytoin in Treatment of Corneal Epithelial Defects in Rabbits

Re-epithelialization of corneal epithelium is a major problem in delayed corneal wound healing. Phenytoin has been used topically for different types of cutaneous wounds and ulcers. The aim of this study was to assess the efficacy of topical phenytoin eye drop and ointment 1% and on the induced sterile corneal epithelial ulcers in rabbit eyes. Fifty eyes from 30 rabbits were evaluated for induction of corneal epithelial ulcer in this study. The right corneas of all rabbits underwent total epithelial debridement. Randomization was made. Odd labeled eyes as control group received artificial tear and even labeled eyes as case group received phenytoin 1% eye drop. Slit lamp examination was performed on day 1, 3, 5, and 7. After healing of the right eyes, the same procedure was performed on 20 corneas of the left eyes. In the left eyes, phenytoin ointment 1% was used instead of phenytoin eye drop 1%. There was no statistically significant difference between corneas that received phenytoin 1% eye drop (n=15) and control group that received placebo (n=15) in the right eyes (P > 0.05). Moreover, difference between corneas received phenytoin ointment 1% (n=10) or placebo (n=10) in the left eyes (P > 0.05) was not significant.The results of this study did not show positive effect of phenytoin on acceleration of healing process in rabbit’s corneal ulcer. Further study in non-healing corneal ulcers is required to show phenytoin efficacy. Phenytoin ointment in comparison to phenytoin drop was better for ophthalmic usage. Application of topical phenytoin 1% in corneal ulcer in rabbits was safe and no severe side effect was observed.