Assessment of Stereoacuity and Fusional Vergence Amplitudes in Children With Autism Spectrum Disorder: A Comparative Study.

Abstract

Purpose: To evaluate the binocular vision and fusion potentials in children diagnosed as having autism spectrum disorder (ASD), while also assessing visual acuity, refractive errors, and the prevalence of strabismus, in comparison with typically developing peers.

Methods: This study included 57 children diagnosed as having ASD and 45 age-matched typically developing children as controls (control group). Comprehensive ophthalmologic examinations were performed in both groups, including best corrected visual acuity (BCVA), biomicroscopic evaluation of anterior and posterior segments, presence of strabismus, measurement of stereoacuity, fusional vergence amplitudes, near point of convergence, and refractive errors. Data and findings were comparatively evaluated between the two groups.

Results: The mean age was 12.10 ± 3.29 years (range: 7 to 18 years) in the ASD group and 10.91 ± 3.08 years (range: 7 to 18 years) in the control group, with no statistically significant difference between the groups (P = .080). A significantly higher prevalence of female participants was observed in the ASD group (P = .003). There was no significant difference in BCVA between the groups (P = .398). Strabismus was detected in 24.56% of the ASD group and 13.33% of the control group. Stereopsis of 480 sec/arc seconds and worse was observed in 47 (82.46%) patients in the ASD group and 4 (8.89%) patients in the control group, with a statistically significant reduction in stereopsis in the ASD group (P = .035). Emmetropia was present in 63.15% of the patients in the ASD group and 40% of the control group, whereas myopia was the most prevalent refractive error for both groups. Fusional amplitudes for convergence and divergence at near distance were found to be lower in the ASD group; however, no statistically significant differences were observed at distance fixation or in near point of convergence measurements.

Conclusions: In children with ASD, stereoacuity and near fusion amplitudes were reduced and the near point of convergence increased. These findings are likely associated with cognitive impairments and attentional deficits characteristic of ASD, potentially rendering near vision tasks particularly challenging. Recognizing and addressing these visual function impairments may facilitate both visual and cognitive development in this patient population.