Experimental evaluation of bacterial corneal ulcer treatment plans using glucocorticosteroid

Abstract

Purpose : to experimentally evaluate treatment plans for bacterial corneal ulcers involving corticosteroid. Material and methods . We used a previously developed model of bacterial corneal ulcer. 40 rabbits (40 eyes) were divided into 4 groups of 10 rabbits (10 eyes) each. Group 1 received topical antibacterial treatment. Groups 2 and 3 additionally received 0.2–0.3 ml injections of 0.1 % Dexamethasone solution once a day (parabulbar and systemic, respectively). Group 4 (control) was clinically observed after corneal ulcer modeling, with no treatment given. The clinical picture and the dynamics of the course of the disease were assessed by biomicroscopy, a fluorescein test, photoregistration and optical coherence tomography of the anterior eye zone (Visante OCT model 1000, Carl Zeiss, Germany). To analyze inflammatory changes and corneal opacities, a quantitative scoring system has been developed. Results . Corneal opacities emerged in the 1 st group of rabbits on the 14 th day from treatment start: in groups 2 and 3, the 9 th day. In group 4, the ulcerous defect remained by day 14. In group 1, a statistically significant thinning of the cornea (by 148.2 ± 32.6 nm) was noted in the ulceration zone after 7 days. The same effect was noted in group 2 (by 363.3 ± 82.0 nm), in the 3rd group 3 (by 362.8 ± 81.2 nm), and in group 4 (by 135.9 ± 40.0 nm). In 90 % of cases in groups 2 and 3, mild corneal opacities without vascularization were formed. In other cases, corneal opacities of high or moderate degree with vascularization were observed. Conclusion . Treatment of bacterial ulcers of rabbit corneas with dexamethasone glucocorticosteroid drug reduces the recovery time as compared to the results achieved through antibacterial treatment alone, as it brings about a rapid drop in the overall inflammatory response and diameter of the ulcer, significant reduction of the edema and infiltration of the cornea, confirmed by AS-OCT. Additionally, such treatment ensures milder corneal opacity and helps avoid corneal vascularization.