Intraocular Pressure and Its Associations in a Russian population: The Ural Eye and Medical Study.

PURPOSE: To assess the normal distribution of intraocular pressure (IOP) and its associations with ocular, medical, and socioeconomic factors in a Russian population.

DESIGN: Population-based cross-sectional study METHODS: The Ural Eye and Medical Study conducted in a rural and urban area in Ufa/Bashkortostan included 5,899 (80.5%) participants out of 7328 eligible individuals aged 40+ years. IOP was measured by non-contact tonometry.

RESULTS: After excluding individuals after glaucoma surgery or with anti-glaucomatous therapy, mean IOP was 13.6±3.8 mmHg (median:13 mm Hg;range:3-49 mmHg; 95% confidence interval (CI):8-23mmHg). The IOP range within the mean ± two standard deviations was 6.0-21.2mmHg. In multivariable analysis higher IOP was associated (regression coefficient r:0.40) with the systemic parameters of female gender (non-standardized regression coefficient B:0.44;95%CI:0.22,0.66;standardized regression coefficient beta:0.06;P<0.001), urban region of habitation (B:-0.27;95%CI:0.51,0.03;beta:0.03;P=0.03), Russian ethnicity (B:0.47;95%CI:0.20,0.74;beta:0.05;P=0.001), higher body mass index (B:0.06;95%CI:0.04,0.08;beta:0.08;P<0.001), lower physical activity score (B:-0.02;95%CI:-0.03,-0.002;beta:-0.03;P=0.02), higher prevalence of diabetes mellitus (B:0.42;95%CI:0.08,0.76 beta:0.03;P=0.02), higher systolic blood pressure (B:0.01;95%CI:0.01,0.02;beta:0.08;P<0.001), fewer days with intake of fruits (B:-0.07;95%CI:-0.12,-0.01;beta:0.03;P=0.01), lower blood concentration of bilirubin (B:-0.01;95%CI:-0.02,-0.003;beta:-0.04;P=0.008) and urea (B:-0.11;95%CI:-0.17,-0.04;beta:-0.04;P=0.003), worse best corrected visual acuity (B:0.64;95%CI:0.38,0.90;beta:0.13;P<0.001), thicker central corneal thickness (B:0.036;95%CI:0.033,0.039;beta:0.32;P<0.001), higher anterior corneal refractive power (B:0.11;95%CI:0.04,0.18;beta:0.05;P=0.003), lower anterior chamber depth (B:-0.57;95%CI:-0.83,-0.30;beta:-0.07;P<0.001) (or lower prevalence of cataract surgery (B:-0.78;95%CI:-1.44,-0.13;beta:-0.03;P=0.02)), longer axial length (B:0.30;95%CI:0.18,0.42;beta:0.07;P<0.001), and higher prevalence of pseudoexfoliation (B:1.08;95%CI:0.52,1.63;beta:1.01;P<0.001). Measured IOP decreased by 0.36mmHg (95%CI:0.33,0.39) for each increase in central corneal thickness by 10 μm.

CONCLUSIONS: IOP was associated with a multitude of systemic and ocular parameters the associations of which may be considered in defining the normal range of IOP.