Liu J, et al. - Researchers explored the connection between the serum vitamin D level and dry eye through a systematic review and meta‐analysis. Using the PubMed, Embase, Web of Science and Cochrane Library databases, a systematic literature search was conducted to identify clinical studies assessing the link between vitamin D levels and dry eye. Overall, 10 studies (n = 18,919) have been involved. Dry eye patients had a mean serum vitamin D level of 3.99 ng/ml below that in healthy controls. Findings suggested an association of vitamin D deficiency with worse subjective symptoms and less tear production in dry eye patients. Deficiency of vitamin D may represent a risk factor for dry eye syndrome. Prospective cohort and intervention studies are warranted to determine whether vitamin D plays a protective role in dry eye development.