Objective: To characterize further a chronic epithelial keratitis caused by varicella-zoster virus infection in patients with acquired immunodeficiency syndrome (AIDS). Methods: Patients with AIDS and chronic epithelial keratitis associated with varicella-zoster virus from 3 institutions were identified. Patient records were reviewed retrospectively for the following data: medical and demographic characteristics, techniques of diagnosis, physical findings, course, response to treatment, and outcome. Results: Sixteen patients were studied. CD4+ T-lymphocyte cell counts were available in 11 patients, with a median of 0.034 x 109/L (range, 0-0.094 x 109/L). Two patients had no history of a zosteriform rash. In the remaining patients, the interval between rash and keratitis ranged from 0 days to 6 years. In all cases, the keratitis was chronic and characterized by gray, elevated, dendriform epithelial lesions that stained variably with fluorescein and rose bengal. The peripheral and midperipheral cornea was most commonly affected, and, in 13 of the 16 patients, the lesions crossed the limbus. Pain was a prominent feature, occurring in 12 of 16 patients. In 9 of 12 patients tested, varicella-zoster virus was identified by culture, direct fluorescent antibody testing, polymerase chain reaction testing, or a combination of these studies, with direct fluorescent antibody testing (6 of 8 positive results) and polymerase chain reaction testing (3 of 3 positive results) appearing to be the most sensitive. Response to antiviral medication was variable. Conclusions: In patients with AIDS, varicella-zoster virus may cause a chronic infection of the corneal epithelium. The keratitis is characterized by dendriform lesions, prolonged course, and frequently by extreme pain. It can occur without an associated dermatitis.