Macular Sublayer Thickness in Healthy Iranian Children: An Optical Coherence Tomography Study from the Population-Based Shiraz Pediatric Eye Study.

Abstract

Purpose: To establish normative values for macular sublayer thickness in healthy Iranian children using optical coherence tomography (OCT) and to assess the effects of age and gender.

Methods: This study was part of the population-based Shiraz pediatric eye study. Of 2400 children aged 6-12 years invited, 480 were randomly selected for optical biometry and macular spectral-domain OCT (SD-OCT) imaging. Finally, 431 OCT scans from children with medium axial length (AL; 21.5-26.5 mm) were analyzed. The OCT device automatically segmented seven retinal sublayers, and their thickness was measured across Early Treatment Diabetic Retinopathy Study (ETDRS) subfields. Thickness in the central 1-mm subfield was assessed by gender and age groups (6-9 vs. 10-12 years), adjusted for AL. Regression analysis examined the impact of age, sex, and AL on retinal sublayer thickness. Only data from the right eye were used.

Results: The mean age of participants was 9.12 ± 1.59 years (range, 6-12), with 254 (58.9%) being girls. The mean AL was 22.91 ± 0.71 mm, and the mean foveal thickness was 258 ± 8 µm. A normative database was created for the total retinal thickness and the seven retinal sublayers across the nine ETDRS subfields. Boys had longer globes (by approximately 0.4 mm; P < 0.001) and thicker foveae (by about 5 µm; P = 0.001) compared to girls. Among the seven sublayers studied, boys had a thicker ganglion cell complex layer (P = 0.014) and outer nuclear layer (ONL; P = 0.012), while girls had a thicker retinal pigment epithelium (RPE; P = 0.029). The inner nuclear layer and outer plexiform layer showed no significant differences (P = 0.075 and P = 0.810, respectively). The mean AL was 22.78 ± 0.68 mm in the 6-9 age group and 23.10 ± 0.72 mm in the 10-12 age group (P < 0.001). The older age group (10-12 years) exhibited thicker ONL (P = 0.009) and RPE (P = 0.002) layers compared to the younger group.

Conclusions: This study provides normative data for macular sublayer thickness in Iranian children aged 6-12 years using Heidelberg SD-OCT. Boys had longer ALs and thicker maculae, while girls had a thicker RPE layer. Older children had longer globes and thicker retinas, mainly due to increased ONL and RPE thickness.