Distribution of intraocular pressure and central corneal thickness by age and gender: a population-based study

PURPOSE: The aim of the study was to examine the distribution of intraocular pressure (IOP) and central corneal thickness (CCT) by age and gender in the Turkish population.
METHODS: In this population-based cross-sectional study, 3556 patients aged 40 years and older in Eskişehir were examined. Demographic, systemic, and eye health questions were asked of all subjects. IOP was measured with a Tono-Pen and a CCT ultrasound pachymeter. Statistical significance was accepted as P < 0.05.
RESULTS: The mean age of the study was 56.86 ± 10.19 and 70.6% were women. The mean IOP was 16.06 ± 3.11 mm Hg and CCT was 553.83 ± 34.34 µm. IOP correlated positively with CCT (r = 0.137; P < 0.001). Age negatively correlated with IOP and CCT (r = −0.057, P < 0.001; r = 0.037, P = 0.05). When evaluated by gender, the mean age of women was 55.99 ± 9.98 years, IOP was 16.21 ± 3.10 mm Hg, and CCT was 552.44 ± 33.90 µm, whereas these values were 58.98 ± 10.41 years, 15.68 ± 3.11 mm Hg, and 557.17 ± 35.17 µm in men (P < 0.001 for each parameter). Multiple regression analysis revealed a significant correlation between IOP and CCT (unstandardized regression coefficient B = 0.013/µm, P < 0.001), age (B = –0.013/year, P < 0.05), and gender (B = 0.551, P < 0.001). CCT proved to be the independent variable with the greatest influence on IOP (standardized regression coefficient beta: 0.141, R2 = 0.028; F = 34.067; P = 0.000).
CONCLUSION: In our study, IOP and CCT decreased with age in both genders. IOP was found to be positively correlated with CCT and female gender and negatively correlated with age, and CCT was the key variable for IOP.