Macular, choroidal, and peripapillary OCT parameters in portuguese schoolchildren: normative data and associations with refractive status

BACKGROUND: Optical coherence tomography (OCT) provides high-resolution structural measurements of the retina, choroid, and optic nerve. Pediatric normative data, particularly in European populations, remain scarce. This study aimed to describe OCT-derived macular, choroidal, and peripapillary parameters in Portuguese children and adolescents (6-18 years) and evaluate associations with refractive status. METHODS: Cross-sectional study including 605 children (127 myopes, 263 emmetropes, 215 hyperopes). OCT parameters included subfoveal choroidal thickness (SFCT), foveal and macular retinal thickness, inner limiting membrane to retinal pigment epithelium (ILM-RPE) volumes, and peripapillary retinal nerve fiber layer (RNFL) metrics. Refractive status, axial length, and visual acuity (LogMAR) were recorded. Data were analyzed using ANOVA or Kruskal-Wallis tests, and multivariate linear regression analyses were performed adjusting for age, sex, axial length, and optic disc area. RESULTS: SFCT was significantly thinner in myopic eyes (298.55 ± 58.52 µm) compared with emmetropes (316.58 ± 51.46 µm; p = 0.001), while hyperopes showed intermediate values (298.70 ± 52.46 µm). Foveal retinal thickness did not differ significantly among groups (p = 0.727). Peripapillary RNFL thickness was reduced in myopes compared with emmetropes in multiple sectors (p < 0.001). Macular ILM-RPE volume and area were slightly lower in myopes (p < 0.05). Axial length was correlated with SFCT (r≈-0.18) and RNFL thickness (r≈-0.30). Multivariate analyses confirmed that SFCT remained independently associated with refractive group after adjustment, whereas RNFL differences were largely explained by axial length and optic disc area. CONCLUSION: This study provides the most comprehensive multi-parameter OCT normative dataset in Portuguese schoolchildren to date, including macular, choroidal, and peripapillary parameters in the largest Portuguese pediatric cohort (n = 605), highlighting refractive error-related structural differences. These data provide population-level normative reference values that may inform clinical and research applications in Portuguese pediatric populations, pending validation in independent cohorts.