Comparative evaluation in the use of topical corticosteroid in the management of corneal alkali burn ulcers in rabbits

This study was performed to evaluate the addition of steroidal or non-steroidal, anti-inflammatory agents or topical medroxyprogesterone acetate to tetracycline and vitamin C in the management of ocular alkali burns. Alkali wounds were created on the central corneas of rabbits by applying a round filter paper, 12 mm in diameter, soaked in 1 M NaOH for 30 s. Only one eye in each rabbit was treated. A total of 25 rabbits were divided into five groups with five animals each. Five rabbits without treatment after the alkali burn were designated as the control group. In the remaining four groups, topical tetracycline and systemic vitamin C treatment were included. In group A, 1% topical medroxyprogesterone acetate, in group B, 1% topical prednisolone acetate and in group C, topical diclofenac were used. In group D, corneal ulcers were treated with only tetracycline and vitamin C. Clinical outcome was monitored daily by corneal opacity, duration of blepharospasm, corneal vascularization, and duration of ocular discharge. After 3 weeks, corneas were excised for histopathological analysis. Samples were monitored by evaluating corneal thickness (ìm), numbers of epithelial rows, keratocyte density, stromal vascularization, stromal inflammation, and stromal collagen arrangement. Comparison between groups showed that groups A, B, and C had significantly lower discharge days, and groups B and C had significantly shorter duration of blepharospasm than the control group. In the microscopic evaluation of the corneas, groups B and C had a significantly lower degree of corneal vascularization, and group B had significantly lower degree of corneal inflammation than the control group. In conclusion, the topical application of 1% prednisolone combined with vitamin C and tetracycline may be therapeutically valuable in the early treatment (first 3 weeks) of corneal alkali burns.