Factors Affecting Intraocular Pressure Measured by Noncontact Tonometer

PURPOSE: To investigate the mean values of intraocular pressure (IOP) measured with noncontact tonometer (NCT) and evaluate the factors that may affect IOP. METHODS: A total of 850 subjects who were admitted to our clinic between March 2005 and February 2006 were recruited for the study. Subjects having blepharitis, conjunctivitis, corneal diseases, glaucoma suspicion, or glaucoma were not accepted to the study. All subjects were questioned about systemic diseases. IOP measurement with NCT and central corneal thickness (CCT) with ultrasound pachymetry were performed for each patient between 9 and 11 AM. RESULTS: The mean ages of 367 (43.2%) male subjects and 483 (56.8%) female subjects were 43.9+/-18.1 and 40.7+/-18.0 years +/- SD, respectively. Since right and left eye IOP, CCT, and keratometric values were significantly correlated, right eye values were used for statistical purposes. Mean IOP values in males and females were 13.2+/-3.0 and 13.5+/-2.9 mmHg, respectively. Mean CCT values were 552.5+/-34.7 mum for males and 550.1+/-34.3 mum for females. In multiple regression analysis, IOP was found to be associated with gender, refractive error, CCT, and the presence of diabetes mellitus (DM). CONCLUSIONS: Gender, CCT, the presence of DM, and refractive error may be significantly associated with IOP in this particular population.