Glaucoma is the second cause of blindness in the world1. In most cases, glaucoma is associated with increased intraocular pressure that develops as a result of impeded outflow of aqueous humor through the trabecular meshwork (TM).2 Selenium is an essential element found in many foods and recently has been touted as a nutritional supplement with chemopreventive properties3. Selenium has been detected in aqueous humor Selenium in aqueous humor is in direct contact with the trabecular meshwork cells in the human eye 4,5 Epidemiological evidence indicates that selenium supplementation may increase risk for glaucoma and ocular hypertension6. The aim of this study was comparing of selenium levels in plasma and aqueous humour in subjects with and without primary open-angle glaucoma (POAG).In addition hemolysate glutathione peroxidase1 (GPx1) and serum gluthatione were compared between subjects with and without POAG.

45 patients with POAG and 45 controls with cataract were enrolled in the study from surgery patients in Tehran University of Medical Sciences hospitals. Potential confounders such as smoking,hypertension and alcohol beverages were assessed via a questionnaire. Biological samples were collected and processed at surgery and analysed for selenium content after collection was complete. Aqueous humour and plasma selenium were determined by atomic absorption(GFAAS technique). The serum selenoprotein P level was measured with ELISA method. The hemolysate GPx1 and serum glutathione were also measured with routine laboratory techniques .

Mean age was 67.91±8.05 in control and 70±7.71 in patients 9(P=0.2) There was significant difference between IOP in two groups. 14.4±2.71 in control versus 24.85±5.67 in POAG patients (p=0<0.0001) The serum selenium was 213.57±48.7ng/ml in controls versus 237.71±43.49ng/ml in patients.(p=0.01)The aqueous humour selenium concentration was significantly high among patients as compared to controls (64.68±13.07 ng/ml vs. 58.36±13.76 ng/ml, P=0.02) The serum selenoproteins p1 was 13.09±10.47µg in control and 46.68±34.38µg in patients.(p<0.001)The serum selenium (P=0.01) and selenoprotein P (P<0.001) levels related significantly to POAG. The results didn’t show a significant difference for the GPx1 activity (P=0.36) between the groups. The intraocular pressure and serum selenoprotein P cut-off points were estimated 39 mmHg (Sensitivity 97.5%); and 189 μg/ml (Sensitivity 93.5% ), respectively

Our results showed the increase in selenium Levels in serum and aqueous may be related to POAG.