Prevalence of acute conjunctivitis caused by chlamydia, adenovirus, and herpes simplex virus in an ophthalmic casualty department.

The causes of acute conjunctivitis in 140 consecutive patients attending an ophthalmic casualty department in London were investigated. Laboratory evidence of infection with Chlamydia trachomatis, adenovirus, or herpes simplex virus was found in 52 (37%) cases. In 70 cases (50%) no evidence of infection with these agents was found. In the remaining 18 cases (13%) laboratory results were inconclusive. The importance of these findings, the role of laboratory investigations in the differential diagnosis of acute conjunctivitis, and their cost-benefit are discussed.