Epidemiological characteristics, predisposing factors and microbiological profiles of infectious corneal ulcers: the Portsmouth corneal ulcer study

Aim: The aim of the study was to identify the epidemiological characteristics, predisposing factors, and the clinical and microbiological diagnosis of infectious corneal ulcers in a population based in southern England. Methods: A retrospective review was undertaken of the medical records of patients presenting with infectious corneal ulcers at the eye casualty department of Queen Alexandra Hospital, Portsmouth, UK, between January 1997 and December 2003. Results: A total of 1786 patients presented with infectious corneal ulcers, with a mean age of 45 years and female predominance (54.5%). Contact lens wear was the main predisposing factor in 554 patients (31%). Corneal scrapes from 1254 patients grew positive cultures in 800 patients. Gram-positive bacteria accounted for 696 (71.1%) of the total 979 bacterial isolates, while Gram-negative bacteria accounted for 283 (28.9%) with the predominance of Pseudomonas aeruginosa. Nine out of 11 patients with Acanthamoeba keratitis were contact lens wearers. The majority of patients 1728 (96.8%) sought medical help more than once and 34 patients (1.9%) had poor visual outcome. Follow-up was completed in 1633 patients (91.4%) with an average of 11.5 days. Conclusions: Wearing contact lenses remains the most important risk factor for infectious corneal ulcers. Reduction of the rate and severity of infectious keratitis requires continuous education of patients, and of professionals.