Slow reading in children with anisometropic amblyopia linked to ocular motor dysfunction

This prospective study ties slow reading to frequent saccades and fixation instability in school-age children with anisometropic amblyopia.

Study design

Researchers compared 40 anisometropic children, 25 of whom had amblyopia, with 25 healthy controls. The children ranged in age from 7 to 12 years. Participants were monitored using the ReadAlyzer eye movement recording system and a video binocular eye tracker while they silently read a grade-appropriate paragraph under binocular viewing conditions.

Outcomes

Previous studies have linked strabismic amblyopia to slow reading. This study examines amblyopic children without strabismus, and finds that they also have slow reading. Affected children with amblyopia read 24% slower than those without amblyopia, and 22% slower than controls. Amblyopic anisometropic children also had more forward saccades compared with children in the other two groups.

Limitations

The study included only children with moderate amblyopia (between 20/32 and 20/80). Furthermore, this analysis of 65 children may not be sufficiently powered to ascertain any relationship with visual acuity.

Clinical significance

This study suggests that amblyopia, not strabismus, is the key factor leading to slow reading in school-age children. Once the amblyopia is treated, children can attain a normal reading speed compared with controls. The study finds no relationship between reading rate and amblyopic eye visual acuity, suggesting that the presence, not severity, of amblyopia determines slower reading in anisometropic children.