The Association Between Subjective and Objective Parameters for the Assessment of Dry-Eye Syndrome

PURPOSE. The aim of the present study was to evaluate the association between symptoms and different clinical signs in patients with dry-eye syndrome (DES). METHODS. Fifty-two patients with DES were included in the present cross-sectional study. For assessment of symptoms, the Ocular Surface Disease Index (OSDI) was used. Clinical parameters included measurement of tear break up time (BUT), corneal fluorescein staining, tear osmolarity, and ocular scattering index (OSI). Tear film thickness (TFT) was assessed using a custom-built optical coherence tomography (OCT) system with an axial resolution of 1.2 mu m. In addition, impression cytology was performed. Correlation coefficients were calculated using linear regression analysis. RESULTS. The mean OSDI in the present study population was 28.9 +/- 17.6, the mean TFT was 4.1 +/- 1.3 mu m. A significant negative correlation was found between OSDI and TFT (r = -0.34, P = 0.01). Tear film thickness correlated positively with BUT (r = 0.35, P = 0.01), but with no other signs of DES. No association was found between OSDI and the other evaluated signs. CONCLUSIONS. The study population mainly comprised of patients with mild to moderate DES. Tear film thickness as measured with a custom-built OCT device correlated with subjective symptoms in these patients. In agreement with previous data, the association between other signs and symptoms was weak in the present study. Measurement of TFT with OCT may become a valuable tool in the management of DES patients.