Preliminary Study: Impact of Strabismus and Surgery on Eye Movements When Children are Reading

To evaluate differences in eye movements during reading in strabismic children and in non-strabismic age-matched children, and to evaluate the potential effect of strabismus surgery on eye movement performance.

The eye movements of nine strabismic children from 11 to 15 years old were recorded with an eye tracker as they were reading a text under three visual conditions before and six months after eye surgery. The results were compared with those obtained from control groups of non-strabismic age-matched children. Eye movements were recorded during reading a text with both eyes open and under monocular vision with the dominant and non-dominant eye alternately covered.

The duration of fixation was longer in strabismic children than in age-matched non-strabismic children. Children read faster under dominant eye open condition than under both eyes open condition. Surgery allowed an increase of reading speed and decrease of fixation duration. The number of backward saccades significantly decreased after surgery.

In strabismic children, eye movements during reading are impaired. The reduction of the squint allowed a better word comprehension.