Abstract
Purpose: :
Using objective methods, the effect of colored overlays on reading eye movements was investigated to determine efficacy. The use of colored overlays or colored lenses has been purported to reduce reading difficulties and symptoms of visual distortions and enhance reading speed. Assessing the efficacy of overlays has to date, been largely subjective.
Methods: :
Using a validated questionnaire to assess vergence, accommodative and ocular motor dysfunction symptom levels, two test groups, (30 subjects per group, age range: 19–31, mean: 25.6yrs, 38 female/22 male) were separated into asymptomatic and symptomatic. Scores of 16 or above on the questionnaire were considered symptomatic while those with scores of 15 or below were asymptomatic. All subjects were evaluated twice at visits separated by at least one month. Subjects read ten randomized age–appropriate passages (Taylor Inc.) with each of ten, randomized, colored overlays (Irlen Institute). Prior to each recording session, the patient was instructed to read for 15 minutes. Eye movements were recorded using a Visagraph by Taylor Inc. Six nested, mixed–effects models were constructed to assess the influence of group, session, color and passage on the dependent variables–response regressions, fixation total number, response span of recognition, comprehension rate, duration of fixation and directional attack percentage.
Results: :
With models taking into account within subject variability, group and passage showed consistent statistical differences across all dependent variables (P<.01). The independent variables, session and color demonstrated no statistical differences. The six models demonstrated that most variability was accounted for within the patient.
Conclusions: :
This study indicates that reading eye movements (fixation, regression, span of recognition, duration of fixation, comprehension rate and directional attack) are NOT affected by the use of colored overlays in either symptomatic or asymptomatic patients. Improvements in reading skills attributed to colored overlays that have been reported in the past have NOT been supported by this objective analysis.
Keywords: eye movements • reading • eye movements: recording techniques