Amblyopic children read more slowly than controls under natural, binocular reading conditions

Abstract

Background: Recent evidence suggests that amblyopia results in fixation instability and atypical saccades. Reading is a vision-reliant ability that requires sequential eye movements, including forward and regressive saccades. This study investigated reading and associated eye movements in school-age amblyopic children.

Methods: Amblyopic children with strabismus and/or anisometropia (n = 29) were compared to nonamblyopic children treated for strabismus (n = 23) and normal control children (n = 21). While fitted with the ReadAlyzer, an eye movement recording system, children silently read a grade-level paragraph of text during binocular viewing. Reading rate, number of forward and regressive saccades per 100 words, and fixation duration were determined. Comprehension was evaluated with a 10-item quiz; only data from children with at least 80% correct responses were included.

Results: Amblyopic children read more slowly and had more saccades compared with nonamblyopic children with treated strabismus and normal controls. Fixation duration did not differ significantly for amblyopic children versus normal controls. Treated strabismic children without amblyopia did not differ significantly from normal controls on any reading measure. Amblyopic eye visual acuity was not correlated with any reading measure.

Conclusions: Amblyopia was associated with slower reading speed in school-age children. Treatment for monocular amblyopia visual acuity impairment could improve reading speed and efficiency.

FIG 1

Bar graphs depicting group means for reading rate, number of forward saccades, number of regressive saccades, and fixation duration for amblyopic children (light gray bars), treated strabismic (or combined mechanism) children without amblyopia (white bars), and normal control children (dark gray bars). Amblyopic children were significantly slower at reading and produced more forward saccades compared with treated strabismic children without amblyopia and normal control children. Error bars represent ± standard error of the mean (SEM). *P < 0.05, **P < 0.01, *** P < 0.001.

FIG 2

Bar graphs depicting group means for reading rate, number of forward saccades, number of regressive saccades, and fixation duration for children with strabismic (or combined mechanism) amblyopia (diamond gray bars) and anisometropic amblyopia (dotted white bars). There were no group differences for any reading measure. Error bars represent SEM.