Efficacy and Safety of Vitamin D Supplementation in Dry Eye Syndrome: A Systematic Review

Dry Eye Syndrome (DES) is a multifactorial disorder impacting tear production and ocular surface health. The increasing prevalence, particularly in the elderly and women, is driven by hormonal changes and external factors. Inflammation is a key element in DES pathophysiology, and recent research suggests vitamin D’s role in modulating inflammation and tear film stability. This systematic review explores the efficacy and safety of vitamin D supplementation in DES. A systematic literature search was conducted across Google Scholar, SpringerLink, and PubMed using keywords like "Dry Eye Syndrome," "Vitamin D," and "randomized controlled trial/observational studies." The final selection comprised six studies, which included randomized controlled trials and observational studies. The Joanna Briggs Institute criteria were used for quality assessment. The reviewed studies demonstrated significant improvements in tear breakup time (TBUT), Schirmer test scores, and ocular surface disease index (OSDI) following vitamin D supplementation. In particular, the studies highlighted vitamin D's ability to enhance the efficacy of conventional treatments like artificial tears. Furthermore, patients with vitamin D deficiency showed better ocular health outcomes with supplementation. No major adverse events were reported, affirming the safety of vitamin D in DES management. Vitamin D supplementation shows potential as a safe and effective adjunctive therapy for improving ocular surface parameters in DES patients, particularly in those with vitamin D deficiency. This highlights the importance of vitamin D in enhancing treatment outcomes for DES.