Intraocular Pressure and Associations in Children. The Gobi Desert Children Eye Study

PURPOSE To assess the intraocular pressure (IOP) and its association in children in a population living in an oasis in the Gobi Desert. METHODS The cross-sectional school-based study included all schools in the Ejina region. The children underwent an ophthalmic examination, non-contact tonometry and measurement of blood pressure and body height and weight. RESULTS Out of eligible 1911 children, 1565 (81.9%) children with a mean age of 11.9±3.5 years (range: 6-21 years) participated. Mean spherical refractive error was -1.58±2.00 diopters. In multivariate analysis, higher IOP (right eye) was associated with younger age (P<0.001; standardized coefficient beta: -0.13; regression coefficient B: -0.13; 95% Confidence interval (CI):-0.18, -0.07), higher diastolic blood pressure (P<0.001;beta:0.13;B:0.05;95%CI:0.03,0.07), higher corneal refractive power (P<0.001;beta:0.11;B:0.23;95%CI:0.12,0.34), more myopic refractive error (P = 0.035;beta: -0.06;B: -0.10;95%CI: -0.19, -0.001), and Han Chinese ethnicity of the father (P = 0.03;beta:0.06;B:0.42;95%CI:0.04,0.89). If age and diastolic blood pressure were dropped, higher IOP was associated with higher estimated cerebrospinal fluid pressure (CSFP) (P<0.001;beta:0.09; B:0.13;95%CI:0.06,0.21) after adjusting for higher corneal refractive power (P<0.001) and Han Chinese ethnicity of the father (P = 0.04). Correspondingly, higher IOP of the left eye was associated with younger age (P<0.001;beta: -0.15;B: -0.16;95%CI: -0.21, -0.10), female gender (P<0.001;beta:0.09;B:0.65;95%CI:0.30,1.01), higher corneal refractive power (P<0.001;beta:0.08;B:0.19;95%CI:0.06,0.32), more myopic refractive error (P = 0.03;beta: -0.06;B: -0.12;95%CI: -0.22, -0.01), and higher estimated CSFP (P<0.001;beta:0.11;B:0.17;95%CI:0.09,0.24). CONCLUSIONS In school children, higher IOP was associated with steeper corneal curvature and with younger age and higher blood pressure, or alternatively, with higher estimated CSFP. Corneal curvature radius should be included in the correction of IOP measurements. The potential association between IOP and CSFP as also assumed in adults may warrant further research.