In this systematic review and meta-analysis, 10 clinical studies were identified that evaluated the association between vitamin D levels and dry eye. Mean serum vitamin D levels were found to be 3.99 ng/ml lower in patients with dry eye than in control patients.
In patients with vitamin D deficiency, mean Ocular Surface Disease Index score was higher and Schirmer’s test without anesthesia result was lower than in control patients.
The authors conclude that, “this meta‐analysis suggested that vitamin D deficiency is associated with worse subjective symptoms and less tear production in patients with dry eye. Vitamin D deficiency may be a risk factor for dry eye syndrome. Prospective cohort and intervention studies are warranted to determine if vitamin D has a protective role in the development of dry eye.”
Liu J, Dong Y, Wang Y. Vitamin D deficiency is associated with dry eye syndrome: a systematic review and meta‐analysis. Acta Ophthalmol. 2020; https://doi.org/10.1111/aos.14470