Vitamin D is best known for its role in bone health, but in recent years researchers have begun exploring its effects on other organs, including the eyes. Several studies have suggested a possible link between circulating vitamin D levels in the blood and the risk of developing age-related eye diseases, but results so far have been mixed. A new study sheds light on this topic, delivering important findings for preventing vision disorders.
The analysis focused on four common eye diseases: cataracts, open-angle glaucoma, age-related macular degeneration (AMD), and diabetic retinopathy. The researchers found a threshold relationship between vitamin D levels and the risk of some of these conditions. In particular, levels below 50 nmol/L were associated with a higher risk of cataracts, AMD, and diabetic retinopathy.
Each 10 nmol/L increase in vitamin D among people with initially low levels was associated with a 3.5% reduction in cataract risk, a 4.2% reduction in AMD risk, and a 6% reduction in diabetic retinopathy risk, but beyond the 50 nmol/L threshold, there did not appear to be any additional benefits. For glaucoma, on the other hand, no significant correlation emerged.
Researchers also sought to understand how vitamin D might exert these protective effects. The analyses suggest that part of the effect could stem from vitamin D’s ability to modulate inflammation and improve glucose and lipid metabolism, two key factors in the development of eye diseases.
These findings underscore the importance of maintaining adequate vitamin D levels, but they also warn against excess: once past the optimal threshold, benefits seem to fade. The ideal approach may therefore lie in targeted supplementation, always evaluated under medical supervision, to protect eye health effectively and safely.
Renato Torlaschi
Study conducted by researchers from Fudan University in Shanghai, China.Huang Z, Liu S, Chen C, et al. Optimizing serum 25(OH)D levels to mitigate the risk of age-related ocular diseases: insights from a large-scale prospective cohort study. Nutrition Journal. 2025 May 31; 24(1):88.
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