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

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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). CONCLUSION: 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.