Gürez, CerenKüçük, Suat Hayri2026-02-132026-02-132025-12European Journal of Clinical and Experimental Medicine T. 23, z. 4 (2025), s. 1021–10262544-1361https://repozytorium.ur.edu.pl/handle/item/12207The study was reviewed and approved by the Bagcilar Training and Research Hospital Ethics Committee with the 2016-493 registration number.Introduction and aim. Dry eye syndrome (DES) is a multifactorial ocular surface disease in which nutritional deficiencies, including fat-soluble vitamins, may play a role. This study aimed to investigate the relationship between serum levels of vitamins A, D, E, and K and DES. Material and methods. A total of 70 eyes from 35 patients with DES and 70 eyes from 35 healthy controls were examined. Dry eye evaluation included tear osmolarity (TO), tear break-up time (TBUT), Schirmer I test, and the Ocular Surface Disease Index (OSDI). Serum vitamin levels (A, D, E, K) were measured using HPLC, LC-MS/MS, and chemiluminescence immunoassay. Results. Patients with DES had significantly higher TO (312.7±4.9 vs. 295.2±6.5 mOsm/L, p<0.001) and OSDI scores (39.8±19.4 vs. 17.2±11.0, p<0.001), and significantly lower Schirmer I (7.0±1.8 vs. 17.3±1.3 mm, p<0.001) and TBUT values (7.3±0.8 vs. 16.1±0.7 s, p<0.001) compared with controls. Serum vitamin A (331.8±87.2 vs. 523.6±109.1 ng/mL, p<0.001) and vitamin D (14.8±6.9 vs. 34.6±14.9 ng/mL, p<0.001) levels were significantly lower in DES patients, whereas vitamin E and K did not differ between groups. Conclusion. Deficiencies in vitamins A and D are associated with impaired tear film parameters and symptoms of DES. These findings suggest that assessing and correcting vitamin A and D deficiency may have clinical relevance in managing DES.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/dry eyetear osmolarityfat-soluble vitaminarticle10.15584/ejcem.2025.4.29