Swabbings from the eyes of 4132 patients attending ophthalmic casualty and outpatients clinics were tested for chlamydiae, adenovirus, and herpes simplex virus. Laboratory isolation tests gave positive results for one of these three agents in 696 (16.8%) cases. When a positive isolation was obtained, only 341 (49%) agreed with the clinical diagnosis while 355 (51%) either had no definite diagnosis marked on the request card or had been clinically diagnosed incorrectly. Routine testing of ocular specimens for all likely organisms can enable the correct treatment to be started sooner than doing one test at each visit, thereby reducing the number of times the patient has to visit the clinic and the expenses involved.