Abstract / Summary
Background: To evaluate the association between serum 25-hydroxyvitamin D [25(OH)D] levels and dry eye disease (DED) in adults attending an ophthalmology outpatient department (OPD), and to assess correlations between vitamin D status and objective ocular surface parameters. Materials and Methods: In this cross-sectional observational study, 210 adults attending the ophthalmology OPD of a tertiary care hospital were enrolled over 12 months. Serum 25(OH)D levels were measured by electrochemiluminescence immunoassay. Vitamin D status was categorised as deficient (<20 ng/mL), insufficient (20–29.9 ng/mL), or sufficient (≥30 ng/mL). DED was diagnosed using TFOS DEWS II criteria incorporating tear film break-up time (TBUT), Schirmer I test, Oxford corneal staining score, and Ocular Surface Disease Index (OSDI). Logistic regression was performed to identify independent predictors of DED. Pearson and Spearman correlations were computed between 25(OH)D and ocular surface parameters. Results: DED was diagnosed in 98 of 210 participants (46.7%). Vitamin D deficiency was present in 118 (56.2%) participants and was significantly more prevalent in those with DED (73.5%) than without (41.1%; p < 0.001). Mean TBUT was significantly lower (5.2 ± 2.1 vs 10.8 ± 3.1 seconds) and mean OSDI score significantly higher (38.4 ± 14.2 vs 11.2 ± 8.4) in the vitamin D-deficient compared with the sufficient group (both p < 0.001). Serum 25(OH)D correlated positively with TBUT (r = +0.624) and Schirmer test values, and negatively with OSDI scores. On multivariate logistic regression, vitamin D deficiency was the strongest independent predictor of DED (adjusted OR 3.42; 95% CI 1.96–5.96; p < 0.001). Conclusion: Vitamin D deficiency is significantly and independently associated with dry eye disease in this Indian tertiary care outpatient population. The strong correlation between 25(OH)D levels and ocular surface parameters suggests a biologically plausible role for vitamin D in lacrimal gland and ocular surface homeostasis. Routine screening for vitamin D deficiency in DED patients, and therapeutic supplementation trials, are warranted. Keywords: Dry Eye Disease, Vitamin D Deficiency, 25-Hydroxyvitamin D, OSDI, Tear Film Break