Relationship between glaucoma and selenium levels in plasma and aqueous humour

Aim: The aim of the study was to compare selenium levels in plasma and aqueous humour in subjects with and without primary open-angle glaucoma (POAG). Methods: Forty-seven POAG cases and 54 controls in this case-control study were recruited from surgery patients at the University Physician's Ophthalmology Clinic in Tucson, Arizona, USA. Aqueous humour and plasma selenium were determined by high-performance liquid chromatography ion channel plasma mass spectrometry (HPLC ICP-MS). Potential confounders were assessed via a questionnaire. Biological samples were collected and processed at surgery and analysed for selenium content after collection was complete. Outcome measures included the odds of glaucoma in relationship to plasma selenium, aqueous humour selenium, and the ratio of levels of aqueous humour selenium to plasma selenium. Results: Tertile of selenium and its relationship to POAG was examined. After adjustment for common glaucoma risk factors, the odds of glaucoma in the highest tertile of plasma selenium (OR = 11.3; p = 0.03) and the middle tertile of aqueous humour selenium (OR = 0.06; p = 0.02) was significantly associated with glaucoma. Conclusion: Although a causal pathway cannot be inferred from our analysis, our data, added to that of others, suggest that the pathology is selenium-related.