Binocular visual function impairment is an independent risk factor in axial length growth and myopia progression

Purpose In order to examine the association between binocular visual function (BVF) impairment and myopia progression, as well as its relationship with axial length (AL), spherical equivalent (SE), and axial length to-corneal radius (AL/CR) ratio. Methods This 9-month longitudinal study involved 949 children [505 males; mean age: 10.96 ± 0.53 years; baseline SE: −0.62 (−1.38, 0.00); baseline AL: 23.80 ± 0.84]. Participants were classified based on the results of three BVF screenings (suppression, simultaneous vision, fusion vision, and stereopsis): those with normal BVF in all screenings were placed in the normal group, those with abnormal BVF in all screenings in the dysfunction group, and the rest in the unstable group. Linear mixed-effects models were used to assess the relationship between BVF status and changes in myopia indicators. Results In the fully adjusted model, BVF status was significantly associated with rapid progression of AL, demonstrating a clear dose-response relationship. The annualized AL growth rate was 0.184 mm/year in the normal group, 0.226 mm/year in the unstable group, and 0.521 mm/year in the dysfunction group. All pairwise comparisons of the growth rates were statistically significant (normal vs. unstable: β = −0.00346 mm/month; normal vs. dysfunction: β = −0.02810 mm/month; unstable vs. dysfunction: β = −0.02463 mm/month; all p < 0.001). In contrast, BVF status showed no significant impact on the progression of SE or AL/CR ratio. Conclusion BVF impairment is an independent risk factor for rapid AL growth, with a clear dose-response relationship. BVF screening could be integrated into routine eye examinations for school-aged children, allowing for early identification of individuals at high risk for rapid myopia progression. Incorporating BVF management into current myopia control strategies could lead to more effective, personalized interventions.