Contact lens-induced infectious keratitis in Japan.

Purpose: To identify microbiologic characteristics of infectious keratitis associated with contact lenses.
Methods: The authors retrospectively examined the microorganism isolated from patients with microbial corneal ulcer associated with contact lenses during a 5-year period. Herpetic and other viral infections were excluded from this study. Patient age, sex, type of contact lens, and isolated organisms were collected from medical records.
Results: Sixty-seven eyes of 66 patients (54.5%) who possibly had contact lens-induced infectious keratitis were reviewed. Cultures of corneal scrapings or eye discharge were positive in 30 (44.8%) of 67 eyes. A total of 35 strains of bacteria were detected, among which there were 29 (82.9%) gram-positive bacteria, two (5.7%) gram-negative bacteria, three (8.6%) fungi, and one (2.9%) species of Acanthamoeba. The most common type of contact lens was a conventional soft contact lens (25 eyes, including extended wear in seven eyes), whereas hard contact lenses, including rigid gas-permeable contact lenses, were worn in 19 eyes. In addition, frequent-replacement lenses were used in 17 eyes, whereas weekly lenses and daily lenses were used for three eyes each. The largest age group was the 20s for all types of lenses.
Conclusions: The results of isolation and culture are essential for improving the cure rate, especially for patients who have severe corneal ulcers.