Correlation between tear crystallization and corneal esthesiometry in patients with Sjögren's syndrome.

PURPOSE: The purpose of this study is to look into the relationship between tear film osmolarity, tear crystallization, and corneal esthesiometry findings in Sjögren's syndrome patients. METHODS: This cross-sectional observational study included 43 eyes from patients with a confirmed diagnosis of Sjögren's syndrome. Tear osmolarity was measured with an iPen osmometer, tear crystallization was graded using Roland's classification, and corneal sensitivity was evaluated with a Cochet-Bonnet aesthesiometer. Ocular symptoms were assessed using the Ocular Surface Disease Index questionnaire. Patients who had undergone keratoplasty or worn contact lenses within 4 hours of testing were excluded. RESULTS: The cohort's mean tear osmolarity was 292.5±15.0 mOsm/L (median: 293 mOsm/L, IQR: 17.5). There was no significant difference between patients with primary Sjögren's syndrome (mean: 289.4 mOsm/L) and those with secondary Sjögren's syndrome (mean: 294.5 mOsm/L; p=0.413). Tear crystallization patterns were more severe in patients with primary Sjögren's syndrome (mean: 3.25, median: 3.5, IQR: 1.25) than in those with secondary Sjögren's syndrome (mean: 3.19, median: 3.0, IQR: 1.0), though the difference was not statistically significant (p=0.87). Corneal sensitivity was reduced by 3.5±1.7 mm (median: 4.0 mm, IQR: 2.13). Tear crystallization has a significant negative correlation with corneal sensitivity (r=-0.313, p=0.041), suggesting that poorer tear quality leads to decreased corneal sensitivity. CONCLUSION: Tear crystallization patterns and corneal sensitivity were found to be significantly correlated in Sjögren's syndrome patients. The findings also indicate that systemic medication use may affect tear film quality.