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

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.

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.

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.

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.