Distribution of and factors associated with intraocular pressure in school-age Chinese children: findings from a large-scale longitudinal study

To report distribution, change trend of intraocular pressure (IOP) and its association with related influencing factors in school-age Chinese children. This retrospective study performed non-contact tonometry, manifest refraction, and ocular biometry in 12,914 participants (25,823 eyes). Univariable and multivariable models assessed the association between the baseline IOP and other baseline parameters, particularly refractive error and axial length (AL). Mixed-effects models evaluated IOP changes with age. Average IOPs of groups aged ≤6 years, 7–9 years, 10–12 years, and >12 years were 14.94 ± 3.13, 15.31 ± 2.93, 15.57 ± 2.85, and 16.12 ± 2.85 mmHg, respectively ( P < 0.001). A higher IOP was associated with thicker central-corneal thickness (CCT, standardised-regression coefficient (SRC): 0.28, P < 0.001), female gender (SRC: 0.18, P < 0.001), longer AL (SRC: 0.08, P < 0.001), deeper anterior chamber (SRC: 0.06, P < 0.001), higher mean-keratometry reading (SRC: 0.04, P < 0.001), higher spherical equivalent (SRC: 0.04, P = 0.002), higher body-mass-index (SRC: 0.03, P < 0.001), higher age (SRC: 0.02, P = 0.02), and smaller White-to-White (SRC: −0.03, P < 0.001). CCT and sex most significantly influenced IOP. There was no significant within-subject change in IOP between baseline and 3-year follow-up ( P = 1.00). In children aged <10 years ( P = 0.02) but not older ( P = 0.19), a higher baseline IOP correlated with greater myopic refraction. The baseline IOP was positively associated with AL ( P < 0.001). The linear regression coefficient decreased with age. CCT and sex most significantly influenced IOP in school-age Chinese children. No significant trend in IOP change corresponding to age increase was found. The association between IOP and myopia or AL became progressively less positive with age.