Dry eye disease and ocular surface characteristics in patients with keratoconus

PURPOSE: The purpose of this study is to investigate the ocular surface alterations in patients with mild or severe keratoconus (KC). METHODS: A total of 80 participants were included in the study. The corneal topography was performed on each participant using Pentacam and the grouping was done accordingly. The patients with Kmax >= 52.0 D (severe KC) were considered Group 1 (n = 28), the patients with Kmax >= 47.2 and <52.0 D (mild KC) were considered Group 2 (n = 30). Healthy control participants with Kmax <47.2 D were considered Group 3 (n = 22). Tear breakup time (TBUT), Schirmer-I test, ocular surface disease index (OSDI) questionnaire, and conjunctival impression cytology (CIC) were evaluated among the groups. RESULTS: The mean values of TBUT and Schirmer-I test were significantly lower (P = 0.012, P = 0.012) and the mean scores of OSDI and CIC were significantly higher (P = 0.006, P < 0.001) in Group 1 and Group 2 than in Group 3. The mean values of TBUT and Schirmer-I test were lower and the mean scores of OSDI and CIC were higher in Group 1 than in Group 2 but the differences were insignificant (P > 0.05 for all). CONCLUSION: These results indicated that the tests associated with dry eye disease are correlated with KC. Tear film alterations and goblet cell loss are higher in severe KC.