Regional macular structure and microvasculature in children with low-to-moderate myopia: a cross-sectional OCT and...

To characterize regional macular retinal thickness and layer-specific optical coherence tomography angiography (OCTA) parameters in children with low-to-moderate myopia and assess their associations with axial length (AL).

This retrospective cross-sectional study included 140 right eyes classified by cycloplegic spherical equivalent refraction (SER) as emmetropia (-0.50 D < SER ≤ +0.75 D; n = 30), low myopia (-3.00 D < SER ≤ -0.50 D; n = 70), or moderate myopia (-6.00 D ≤ SER ≤ -3.00 D; n = 40). Macular structural OCT and layer-specific OCTA images were acquired with a Heidelberg Spectralis OCT system with eye tracking; associations with AL were assessed by multivariable regression.

Participants were aged 8-14 years; 73 (52.1%) were boys and 67 (47.9%) were girls, with no significant between-group differences in age or sex. Retinal thickness differed among groups in the superior and inferior parafoveal and temporal perifoveal sectors. Superficial vascular complex (SVC) foveal avascular zone (FAZ) area (overall P = 0.002) and perimeter (overall P = 0.014) differed among groups. Both were greater in moderate-myopic than low-myopic eyes (area: 0.57 ± 0.08 vs 0.51 ± 0.10 mm², P = 0.001; perimeter: 3.14 ± 0.22 vs 2.96 ± 0.41 mm, P = 0.012), whereas neither differed significantly between emmetropic eyes and either myopic group. SVC vessel area density, vessel length density, and fractal dimension did not differ among groups, and no overall between-group differences were found for deep vascular complex or intermediate capillary plexus parameters. In the deep capillary plexus, moderate-myopic eyes had lower vessel length density than emmetropic eyes, lower fractal dimension than both other groups, and larger FAZ area and perimeter than low-myopic eyes. Longer AL was independently associated with larger SVC FAZ area and perimeter and thinner superior, nasal, and temporal perifoveal retina. Central foveal retinal thickness was inversely associated with FAZ area across all four vascular layers.

In children with emmetropia and low-to-moderate myopia, differences in macular structure and OCTA parameters exhibit regional and layer-specific characteristics. Differences in the area and perimeter of the FAZ in the SVC were observed exclusively between the moderate myopia and low myopia groups. Furthermore, longer axial length was independently associated with larger SVC FAZ area and perimeter, as well as thinning of the parafoveal retina in the superior, nasal, and temporal regions.