Trends in Microbial Keratitis in Japan

Purpose: To identify microbiologic characteristics of infectious keratitis and predisposing factors.

Methods: The microorganisms isolated from patients with infectious corneal ulcers during the 5 years between January 1999 and December 2003 were retrospectively examined. Herpetic and other viral infections were excluded from this study. Patient age, sex, risk factors, and isolated organisms were collected.

Results: In 123 eyes of 122 patients, organisms were isolated from 72 (58.5%) eyes. In total, 99 different organisms were isolated. Among these, 77 (77.8%) were gram-positive bacteria; 18 (18.2%) were gram-negative bacteria; six (6.1%) were fungi; and one (1.0%) was acanthamoeba. Contact lens wear was the main risk factor (54.5%), and ocular surface disease and previous ocular surgery were present in 20.5% and 13.1% of cases, respectively. Posttreatment visual acuity was significantly improved by pretreatment in culture-positive groups treated according to the antibiotic susceptibilities (Wilcoxon t test, P<0.01).

Conclusions: The results are changing to those reported by other countries and generations. Contact lens wear is the most important risk factor in Japan. The results of isolation and culture are essential for improving the cure rate.