Risk factors for herpes simplex-induced keratitis: a case-control study.

Forty-two patients at three institutions were compared with control subjects with regard to the prevalence of risk factors for herpes simplex-induced keratitis (HSK) that have been postulated in the literature. The patients' average age was 46.3 years; their average age at the first episode of HSK was 41.7 years. Seventy-five percent of the patients had recurrent HSK. The infection was bilateral in 11.76% of the patients. There was no seasonal variation in the onset of HSK. Furthermore, there was no statistical association between HSK and male sex, atopy, corticosteroid use, intraocular trauma, contact lens wear, or herpes labialis infection. This pilot study raises issues regarding the design of future investigations of the epidemiology of this infection.