Intraocular pressure and optic disc cupping in school-aged children: An epidemiological study in Taiwan

The purpose of the study was to investigate intraocular pressure (IOP), cup-to-disc ratio (CDR), and ocular biometrics in school-aged children in Taiwan and to evaluate the factors associated with IOP and CDR.

This nationwide school-based study prospectively enrolled children aged 6-18 years. Cycloplegic autorefraction, A-scan ultrasonography, IOP measurement with a rebound tonometer, and CDR assessment with indirect ophthalmoscopy were performed. High myopia (HM) was defined as spherical equivalent (SE) <-5.00 diopters or axial length (AL) ≥26 mm. Linear mixed-effects models evaluated the associations between ocular parameters, age, and sex and identified factors associated with IOP and CDR.

We enrolled 6264 eyes from 3132 children (1435 girls and 1697 boys; mean age 12.1 ± 3.4 years; mean IOP 17.2 ± 2.6 mmHg). The median CDR was 0.3 (range: 0.1-0.9); 10.8% of eyes had a CDR >0.4, and 1.8% had a CDR >0.6. The overall prevalence of HM was 8.0%, increasing to 25.4% at age 17. AL, anterior and vitreous chamber depth, IOP, and CDR all increased with age (all P < 0.001, except IOP, P = 0.006), whereas lens thickness and SE decreased (P < 0.001). AL was independently associated with IOP (β = 0.118, P = 0.010) and CDR (β = 0.006, P < 0.001). Among adolescents aged 15-18 years, HM eyes had significantly greater IOP than non-HM eyes (18.0 ± 3.2 vs. 17.2 ± 2.7 mmHg, P < 0.001). In HM eyes, greater IOP correlated with larger CDR (β = 0.005, P = 0.020).

In school-aged children, IOP and CDR showed a slight increase with age. AL was an important determinant of IOP and CDR. HM may amplify the interaction among IOP, CDR, and AL.