OFLOXACIN MONOTHERAPY FOR THE PRIMARY-TREATMENT OF MICROBIAL KERATITIS - A DOUBLE-MASKED, RANDOMIZED, CONTROLLED TRIAL WITH CONVENTIONAL DUAL THERAPY

Background: Ofloxacin is a potent broad-spectrum fluoroquinolone antib iotic commercially available as a topical ophthalmic preparation. The authors compared ofloxacin (0.3%) as a single therapy with their conve ntional dual therapy of specially prepared, fortified gentamicin (1.5% ) and cefuroxime (5.0%) drops for the treatment of suspected microbial keratitis. Methods: The authors enrolled 122 patients with a clinical diagnosis of microbial keratitis in a prospective, randomized, contro lled, double-masked study to compare the two therapies. The ofloxacin drops were decanted into identical-looking bottles to the conventional treatment and dispensed with a second bottle containing saline only. The initial and subsequent assessments noted any risk factors, the siz e and location of the ulcer, and any evidence of corneal and conjuncti val toxicity. All ulcers were scraped for microbiologic culture, and i solated organisms were tested for sensitivity to the trial antibiotics . For statistical analysis, a ''cure'' was defined as complete healing of the ulcer (no epithelial defect). A ratio of the two outcome propo rtions and its confidence limits was used to compare the two treatment groups. Multiple regression analysis using Poisson models was used to adjust for confounding factors that may have modified the outcome rat ios. Results: There was no difference in the treatment success between the two treatments, with 67.9% of the conventional treatment group an d 62.1% of the ofloxacin group being cured within 14 days (ratio, 1.09 ; [95% confidence interval, 0.83-1.43]; P = 0.59). However, there was significantly more toxicity encountered with the conventional treatmen t group (50.8% vs. 10.2%; ratio, 5.00 [95% confidence interval, 2.25-1 1.11]; P < 0.0001). Poisson regression with adjustment for confounders did not materially change the ratio proportions for either treatment success or toxicity, There was at least a 90% chance to detect a 30% d ifference between the groups. Conclusions: The authors found that the treatment outcomes with ofloxacin monotherapy compared favorably with their conventional therapy and were associated with less toxicity.