Dyslexia and eye movements

Abstract

AbstractPurpose To analyze the relationship between dyslexia and eye movements. Methods 22 patients were included in the study, 11 patients have a diagnosis of dyslexia and 11 subjects were used as a control group (normal readers). The age of patients enrolled ranged from 8 to 13 years. All patients underwent careful orthoptic and ophthalmological visit; eye movements were quantified by Ober‐2 system. Ocular motility was divided into three phases: stability analysis to while fizating a still target; analysis of fixation pauses, analysis of tracking saccades (left and right horizontal axis); speed reading, saccades and regressions through the reading of a text.Results The stability analysis on fixating a still target showed a significant (p<0.001) difference between dyslexic and control group, outlining an increased amount of loss of fixation in dyslexic subjects (5.36 +/‐ 2.5 and 0.82 +/‐ 2.1, respectively). Only two patients in the control group presented a fixation loss while none in the study group presented this defect. Also tracking saccades (left and right horizontal axis) and loss of fixation after saccades did not show significant difference. When the reading time was analyzed, a significant (p<0.001) difference was found between the dyslexic subjects and the control group (90+/‐ 52.0 second and 42 +/‐ 17.3, respectively). When the regression saccades were analyzed, a significant (p<0.001) difference was found between the dyslexic subjects and the control group (52+/‐ 33.4 seconds and 20.3 +/‐ 11.3, respectively).Conclusion This is the first report of some ocular movement difference between dyslexic and healthy subjects detected by using the Ober‐2 system. Should our findings be confirmed, this analysis could be added to the work‐up of dyslexic.