Increased homocysteine levels in tear fluid of patients with primary open-angle glaucoma.

AIMS We assessed homocysteine (Hcy) levels in tear fluid and plasma of patients with primary open-angle glaucoma (POAG). We determined the association between Hcy levels, dry eye syndrome and B vitamin status. METHODS This prospective case-control study included 36 patients with POAG and 36 controls. Hcy concentrations were measured by high-performance liquid chromatography. RESULTS Patients with POAG had significantly higher mean Hcy levels both in tear fluid (205 +/- 84 nmol/l; p < 0.001, t test) and in plasma (13.43 +/- 3.53 micromol/l; p = 0.001, t test) than control subjects (130 +/- 53 nmol/l and 10.50 +/- 3.33 micromol/l, respectively). Hcy in tear fluid was significantly correlated with plasma Hcy in POAG patients (r = 0.459; p = 0.005, Pearson's correlation), but not in controls (r = 0.068; p = 0.695). POAG patients with dry eye disease had significantly higher Hcy levels both in tear fluid and plasma than POAG patients without dry eye disease. There was no association between Hcy levels and B vitamin status in subjects with POAG. CONCLUSIONS The study suggests increased Hcy levels in tear fluid and plasma of patients with POAG. Elevated Hcy levels might be a risk factor for POAG and dry eye syndrome in subjects with glaucoma.