Association between fusion visual function deficits and myopia in school-aged children: an analysis based on competitive binocular vision screening

Even after refractive correction, myopic children remain at a significantly higher risk of visual function deficits compared to non-myopic children. Competitive binocular visual function testing is a screening method designed to simulate complex visual environments, specifically developed for the large-scale and rapid assessment of children’s visual performance under challenging conditions. This study aims to investigate whether visual function deficits observed in simulated complex environments are associated with myopia, thereby informing potential strategies for myopia prevention and control. A cross-sectional study was conducted involving 1,430 school-aged children from grades 1 to 6 at an elementary school in Wuxi in 2022. Competitive binocular visual functions (simultaneous perception, fusion, and stereopsis) were assessed and compared between myopic and non-myopic children. The rate of fusion function deficits in the myopic group (35.80%, 256/715) was significantly higher than that in the non-myopic group (26.57%, 190/715). Myopic children had a 1.54 times higher risk of fusion deficits compared to non-myopic children (OR=1.54, 95% CI: 1.22–1.94). A weak positive correlation was observed between the degree of myopia and fusion deficits (r=0.087, P<0.01). Age stratification revealed that the fusion deficit rate in the lower-grade group (7–9 years old) (50.62%, 365/721) was significantly higher than that in the higher-grade group (10–12 years old) (11.42%, 81/709). Younger children had an 8.05 times higher risk of fusion deficits compared to older children (OR=8.05, 95% CI: 6.18–10.49). Gender differences showed that the fusion deficit rate in males (46.89%, 332/708) was significantly higher than that in females (15.79%, 114/722), with males having a 4.63 times higher risk than females (OR=4.63, 95% CI:3.64–5.89). No significant differences were observed in simultaneous perception or stereopsis between the myopic and non-myopic groups (P > 0.05). Myopic children are more likely to exhibit deficits in competitive binocular fusion function. These findings indicate that early childhood may represent a potential critical period for intervention in fusion function development.