Predictive factors for response to medical therapy in bacterial ulcerative keratitis

Background: Fifty-four consecutive cases of culture-positive bacterial ulcerative keratitis presenting at a major university hospital were reviewed to identify factors predictive of response to medical therapy for bacterial ulcerative keratitis (BUK). Methods: Eleven patients (20%) failed medical therapy (defined as the need for surgical intervention or cyanoacrylate gluing). Using multivariate logistic regression, the following variables were evaluated: (1) predisposing ocular factors (e.g., contact lens wear), (2) pre-existing ocular diseases, (3) ulcer size, and (4) the number of topical ocular medications used at the time of presentation. Results: We noted certain factors to be potentially predictive of medical therapy outcome. The average size of the ulcer at the time of presentation was 4.4±2.4 mm in the failure group but only 2.5±1.9 mm for the success group (P=0.027). In addition, patients in the medical failure group used more topical ocular medications at the time of presentation (P=0.0075). Further analysis of the individual topical ocular medications revealed that the use of corticosteroids was higher in the failure group (56% vs 12%, P=0.0005 by Fisher's exact test). Other factors such as patient age, the type of organism(s), and the time elapsed between the onset of symptoms and the beginning of definitive therapy were not statistically significant. Conclusion: In this population, ulcer size at the onset of antibacterial treatment and the use of certain ocular medications, specifically corticosteroids, were significant predictive factors for failure of medical therapy for BUK.