We reviewed the charts of 67 patients with the diagnosis of normal-tension glaucoma listed in the Bascom Palmer Eye Institute computer database. These patients were matched with respect to age, race, and sex with an equal number of patients having ocular hypertension. All medical diagnoses in the charts for both groups were tabulated and classified as either immune-related or non-immune-related. Twenty (30%) patients with normal-tension glaucoma had one or more immune-related disease(s) compared with five (8%) patients in the comparison group (P = .00134, McNemar statistic with continuity correction).