Serum vitamin D status is associated with the presence but not the severity of primary open angle glaucoma.

OBJECTIVES Vitamin D is involved in visual health and function. Our objective was to determine whether age-related vitamin D insufficiency was associated with the presence and the severity of primary open angle glaucoma (POAG) in a case-control study of older adults. STUDY DESIGN Case-control study. MAIN OUTCOME MEASURES One hundred fifty cases diagnosed with moderate-to-severe POAG (mean, 75.1 ± 8.5 years; 42.0% female) and 164 healthy controls (mean, 73.0 ± 7.9 years; 59.8% female) were included. POAG diagnosis was based on classical diagnostic criteria of optic nerve cupping and/or RNFL thinning, measured with optical coherence tomography. Severe POAG was defined as Humphrey visual field mean deviation (MD) worse than -12 dB. Vitamin D insufficiency was defined as serum 25OHD ≤ 75 nmol/L. Age, gender, mean arterial pressure, vitamin D supplementation, visual acuity, and intraocular pressure were used as potential confounders. RESULTS POAG cases had lower mean serum 25OHD concentration than controls (42.9 ± 25.7 nmol/L versus 49.4 ± 29.5 nmol/L, P=0.039) and a greater prevalence of vitamin D insufficiency (90.7% versus 82.3%, P=0.032). Increased mean serum 25OHD concentrations were associated with lower POAG frequency, even after adjustment for potential confounders (OR=0.89 per 10 nmol/L of 25OHD, P=0.045). Similarly, vitamin D insufficiency was associated with POAG (OR=2.09, P=0.034). Among POAG cases, no 25OHD difference was observed between moderate and severe POAG cases (respectively, 39.2 ± 23.3 nmol/L versus 45.1 ± 26.7 nmol/L, P=0.188); and no between-group difference regarding the prevalence of vitamin D insufficiency (88.9% versus 94.0%, P=0.313). CONCLUSIONS Decreased serum 25OHD concentration was associated with POAG. There was no 25OHD difference between moderate and severe POAG.