We examined aqueous humor levels of 25-hydroxyvitamin D (vitamin D) in patients with age-related macular degeneration to investigate possible relationships between aqueous humor vitamin D levels and clinical manifestations.

Patients > 50 years of age, 52 eyes of 34 patients with age-related macular degeneration, and 23 eyes of 17 patients treated with cataract surgery without retinal disease, were examined for aqueous humor vitamin D levels and compared. The experimental group was divided into two groups according to the median value of aqueous humor vitamin D levels. We compared the clinical manifestations of macular degeneration in both groups and identified relationships between aqueous humor vitamin D levels and clinical features.

Vitamin D levels in the aqueous humor were significantly lower in the experimental group than in the control group (experimental, 10.03 ± 10.1 ng/mL vs. control group, 40.8 ± 16.4 ng/mL; p < 0.001). Patients with high vitamin D levels in the macular degeneration group had a higher percentage of fibrovascular pigment epithelial detachments than those in the low grade group (high grade group, 65% vs. low grade group, 27%; p = 0.003). Multiple linear regression analysis showed a significant correlation between vitamin D levels and the total number of anti-vascular endothelial growth factor intravitreal injections within 6 months (standardize coefficient, β = −0.336).

Patients with wet age-related macular degeneration had significantly lower vitamin D levels in the aqueous humor compared to control group subjects of similar ages. However, in patients with macular degeneration, low vitamin D levels were associated with a greater number of intravitreal injections, while higher levels of vitamin D may lead to more advanced forms of fibrovascular retinal pigment epithelium and related low vision. These relationships were not always constant, so further studies on the relationships between local vitamin D levels and ocular disorders are needed.