Related Experiment Video
Updated: Oct 24, 2026
Assessing Binocular Central Visual Field and Binocular Eye Movements in a Dichoptic Viewing Condition
Published on: July 21, 2020
The relationship between binocular vision components and visual evoked potentials with reading difficulties in
Alireza Jamali1, Razieh Ahangarani1, Mehdi Khabazkhoob2
1Rehabilitation Research Center, Department of Optometry, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran.
Purpose:
To assess the relationship between visual function and neural processing with reading/writing defects in elementary school children.
Methods:
This case-control study included 28 boys (8-12 years old) with poor academic performance (study group) and 14 healthy, age-matched controls. All participants underwent a comprehensive optometric evaluation, including visual acuity, refractive error, heterophoria, accommodation and convergence facility, fusional reserves, and monocular Visual evoked potentials (VEPs) using 15- and 60-checkerboard patterns (ISCEV standards).
Results:
No significant differences were found in uncorrected or best-corrected visual acuity between groups (p > .05). However, the study group demonstrated significantly greater hyperopia (+0.07 ± 0.61 D vs. -0.12 ± 0.23 D, p = .025), reduced monocular (6.93 vs. 9.07 cycles/min, p < .001) and binocular (6.04 vs. 8.00 cycles/min, p < .001) accommodative facility, as well as lower vergence facility (6.93 vs. 8.71 cycles/min, p < .001). The study group also exhibited greater exophoria at near (4.61 Δ vs. 2.57 Δ, p < .001) and a reduced distance base-out blur point (10.36 Δ vs. 11.71 Δ, p = .043). VEP measurements revealed a significantly prolonged P100 latency at the 15' check size (112.86 vs. 109.07 ms, p = .043) and higher Fmod values at both 15' (p = .029) and 60' (p = .031) in the study group compared to controls.
Conclusion:
Children with reading difficulties exhibit distinct subclinical visual deficits, particularly in accommodative function, alongside delayed neural processing despite normal visual acuity. Binocular functional assessments and neurophysiological tests should be integrated into assessments of poor academic performance.
