Dry eye in vitamin D deficiency: more than an incidental association

AimThe aim of this article is two-fold: (i) to demonstrate the relation between vitamin D deficiency and dry eye and impaired tear function; and (ii) to investigate the possible associations among clinical parameters of hypovitaminosis D with dry eye parameters. MethodFifty premenopausal women with vitamin D deficiency (serum vitamin D levels <20ng/mL) and 48 controls were included. Participants were assessed by Schirmer's test, tear break-up time test (TBUT), ocular surface disease index (OSDI), Stanford Health Assessment Questionnaire (HAQ), fatigue severity scale (FSS), and visual analogue scale-pain (VAS-pain). ResultsLower scores in Schirmer's test and TBUT, and higher in OSDI were detected in patients with vitamin D deficiency than in controls (P<0.05). FSS was negatively correlated with Schirmer's test (r=-0,29; P=0.038) and TBUT scores (r=-0,43; P=0.002); VAS-pain was negatively correlated with TBUT scores (r=-0.32; P=0.023). HAQ scores showed no significant correlation with dry eye parameters (P>0.05). Vitamin D level was negatively correlated with OSDI (r=-0.49; P<0.001), and positively with Schirmer's test (r=0.45; P=0.001) and TBUT scores (r=0.30; P=0.029). ConclusionDry eye and impaired tear function in patients with vitamin D deficiency may indicate a protective role of vitamin D in the development of dry eye, probably by enhancing tear film parameters and reducing ocular surface inflammation. Patients with vitamin D deficiency should be evaluated for dry eye syndromes.