Retinal curvature in Chinese children with myopia measured by ultra-widefield swept-source optical coherence tomography.

Aims: To quantitatively measure retinal curvature (RC) in children with myopia and explore its association with refractive status.

Methods: This cross-sectional study included participants aged 5-18 years who underwent comprehensive ocular examinations, including cycloplegic refraction and macula 24×20 mm optical coherence tomography (OCT) scans. RC was derived from OCT data using a three-dimensional reconstruction system. Mean RC was assessed in concentric circles (RC I-VI) with diameters of 1, 3, 6, 9, 12 and 15 mm around the fovea, as well as in four orientations (RC S/I/N/T).

Results: A total of 443 eyes were included in the analysis. The values from RC I to RC VI were 0.51±0.19, 0.53±0.19, 0.62±0.19, 0.76±0.23, 0.86±0.23 and 0.81±0.18 10^-2mm^-2, respectively. RC I exhibited the smallest curvature, while RC V displayed the highest (p<0.001). High myopia (HM) group demonstrated larger RC I and smaller RC III/IV/V/VI compared with low myopia (LM) group (p<0.01). Significant differences among RC S/I/N/T were observed in HM group (pairwise comparison, p<0.001), but not in LM group. Multiple regression analysis revealed that age, sex, corneal curvature radius and subfoveal choroidal thickness (SFCT) were associated factors with foveal RC, while age, SFCT and axial length (AL) were associated factors of peripheral RC.

Conclusion: RC can quantitatively characterise retinal shape and the morphological changes induced by myopia. Myopia progression results in a bulging macular retina accompanied by a flattening peripheral retina in children, and also increases the irregularity among the four quadrants. Age, AL and SFCT are associated factors of RC.