A Comparison of Reading Speeds of Intermittent Exotropia and Normal Children

Purpose: We investigated the reading speeds of elementary school-aged children with or without intermittent exotropia. Methods: Children between the ages of 7 and 12 years with intermittent exotropia without amblyopia (n = 37) and normal-sighted children (n = 37) were included. Near-stereopsis and fusion were evaluated. Reading speeds were calculated using a Korean reading speed application, twice: once for reading the sentence silently (reading only) and a second time for reading the sentence aloud (reading & speaking). Reading speed was recorded in words per minute (WPM) and letters per minute (LPM) according to the size of the letters. The factors related to reading speed were analyzed, and the reading speeds of the two groups were compared. Results: The rate of fusion at far and near extremes was lower in the intermittent exotropia group than in the control group (p = 0.028). There was a significant correlation between age and reading only speed and reading & speaking speed for both groups (p = 0.006, p = 0.004). Both WPM and LPM reading speeds of the reading only intermittent exotropia group were slower than those of the control group (p = 0.048, p = 0.050); however, the differences between groups became more pronounced after correction for the age distribution (p = 0.029, p = 0.035). LPM reading speed for middle-sized letters was significantly slower in the intermittent exotropia group than in the control group (p = 0.046). There was no statistical difference between the two groups regarding the reading speed or reading & speaking speed. Conclusions: the reading only and reading & speaking speeds increased with the age of the student, regardless of whether the student had intermittent exotropia. The reading only speed was considerably slower in the intermittent exotropia group. Thus, measures should be taken to monitor the reading development of younger school-aged children with intermittent exotropia carefully to allow for early intervention should issues arise.