BACKGROUND A causal relationship between glaucoma and obstructive sleep apnea has been postulated in several clinical studies but also refuted by others. The aim of this study was to determine the prevalence of glaucoma in a cohort of patients with well-established obstructive sleep apnea in comparison to the published data on this topic. METHODS A total of 100 consecutive patients (male:female 80:20, mean age 59 ± 11 years SD) with polysomnographically established obstructive sleep apnea underwent an ophthalmological examination including tonometry, static perimetry and dilated fundus photography. Visual fields and fundus photographs of the patients were classified as glaucomatous or non-glaucomatous by two independent examiners. RESULTS The prevalence of glaucoma in the study patients was 2 % which corresponded to the published prevalence of glaucoma in the normal population. Intraocular pressure did not correlate with the respiratory index, body mass index or sex. CONCLUSION The data from this study shed doubt on a causal relationship between obstructive sleep apnea and glaucoma.