Increased Vertical Asymmetry of Macular Retinal Layers in Myopic Chinese Children

Purpose: The purpose of this project is to explore the changes in and factors associated with asymmetry between the superior and inferior hemiretina in children with different refractive levels. Materials and Methods: A total of 2964 children from 12 primary and middle schools in Shanghai, China, were included. The mean thickness of the GCL+ layer (ganglion cell layer+ inner plexiform layer), the GCC layer (ganglion cell complex, a combination of the retinal nerve fiber layer and the GCL+ layer), and the neural retina was measured according to the sectors defined by the Early Treatment of Diabetic Retinopathy Study (ETDRS) grid with swept-source optical coherence tomography. The asymmetry index (AI), calculated via the formula AI = |log(10) (superior/inferior hemiretinal layer thickness) |, was used to assess the asymmetry of each retinal layer. Results: The mean age of the children was 11.67 (3.45) years old. The AIs of all retinal layers were larger in myopes than in hyperopes and emmetropes in the perifoveal region (all p < 0.001), and the AIs became even larger in the GCL+ layer and neural retina in children with a higher degree of myopia. However, no statistical differences were observed between various refractive groups in the parafoveal region. Regression analyses indicated that with increasing myopia, the asymmetry of retinal layers increased in the perifoveal region (all p < 0.001) and slightly decreased in the parafoveal region (all p < 0.05). Conclusions and relevance: The vertical asymmetry of retinal layers increased in the perifoveal region in myopic children, and the change in asymmetry was more obvious in the GCL+ layer and neural retina than in the GCC layer.