Topical use of zinc desferrioxamine for corneal alkali injury in a rabbit model

Purpose. To evaluate the efficacy of topical zinc desferrioxamine in acute corneal alkali injury in rabbits. Methods. Twenty rabbits were anesthetized and a standardized alkali bum (1N NaOH) was performed in the center of the cornea (7.5-mm diameter). The animals were randomly divided into two groups and treated (double-masked) with topical zinc desferrioxamine, 220 μM, (group 1) or its vehicle (group 2). Drops were applied 7 times/day for 28 days. Topical gentamicin, 0.3%, was instilled twice a day. Animals were evaluated twice a week. At each examination (using the slit-lamp), the depth of corneal ulcer was graded as follows: 0, no ulcer; 1, tissue loss less than one third of corneal thickness; 2, one third to two thirds tissue loss; 3, more than two thirds tissue loss; 4, descemetocele; or 5, perforation, Ulceration area, vascularization, and epithelial defects also were measured. Results. During the study period, the grading of mean corneal ulcerations in group 1 ranged from 0.2 to 1.00, whereas in group 2, it ranged from 1.4 to 2.7. The mean grade and area of ulceration in group 2 were greater than those in group 1 (p < 0.05). Conclusion. Topical zinc desferrioxamine may be an adjunctive treatment in protecting the cornea against induced alkali injury.