Amblyopic Children Read More Slowly Than Controls Under Natural, Binocular Reading Conditions
Presented at the 41st Annual Meeting of the American Association for Pediatric Ophthalmology and Strabismus, New Orleans, Louisiana, March 25-29, 2015.
- Eye movements while reading grade-level text at the habitual reading distance were recorded in a small cohort of school-aged children with amblyopia (lazy eye), with or without strabismus (an eye turn in or eye turn out). Compared with normal controls and strabismic children without amblyopia, children with amblyopia had a significantly slower reading rate and made significantly more forward saccades. (a saccade is a jump eye movement when moving from one thing you are looking at , to another. When we read, we look at one word and then jump to the next word. When we reach the end of a line of print, we saccade, jump our eyes, from the end of that line to the start of the next line. If we cannot do that accurately, then reading is labored and not smooth. We spend energy on the eye movement part of reading and do not have enough for understanding what we are reading.
- The authors conclude that amblyopia rather than strabismus is responsible for slower reading rates and suggest that this could be due to oculomotor dysfunction (increased number of saccades) or to the visual acuity deficit. They further suggest that children with amblyopia (even with binocular 20/20 acuity) should be given academic accommodations such as increased time to complete assignments.
This study is very important because it further points out the false sense of security that when a child has 20/20 with both eyes together there is no significant visual impediment to reading.
The studies before this one had concentrated on strabismic amblyopia, whereas this study focused on amblyopia without strabismus.
The authors used the ReadAlyzer device, a device we have in our office, that enabled them to document eye movement reading patterns objectively.
Poor eye movement deficits were not a secondary manifestation of poor comprehension. Rather, it is the reason for the poor comprehension.
The authors of the study stress the importance of recognizing amblyopia as a potential reason to request accommodation in school or on standardized testing for a student to receive additional time for completion of assignments.
They also note the importance of treating amblyopia because of the implications for improved transfer effects to reading.
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.
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.
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.
Amblyopia was associated with slower reading in school-age children. Treatment for monocular amblyopia visual acuity impairment could improve reading speed and efficiency.