Evaluation of ocular movements in patients with dyslexia
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The aims of this study were to analyze the relationship between dyslexia and eye movements and to assess whether this method can be added to the workup of dyslexic patients. The sample was comprised of 11 children with a diagnosis of dyslexia and 11 normal between 8 and 13 years of age. All subjects underwent orthoptic evaluation, ophthalmological examinations, and eye movement analysis, specifically, stability analysis on fixating a still target, tracking saccades, analysis of fixation pauses, speed reading, saccades, and regressions through the reading of a text. Stability analysis on fixating a still target showed a significant (p < 0.001) difference between the two groups showing an increased amount of loss of fixation among dyslexic subjects (5.36 ± 2.5 s and 0.82 ± 2.1, respectively). Tracking saccades (left and right horizontal axis) did not show a significant difference. When reading parameters were looked into (number of saccades, number of regressions, reading time through the reading of a text), a significant (p < 0.001) difference was found between the groups. This study supports the belief that the alteration of eye movement does not depend on oculo-motor dysfunction but is secondary to a defect in the visual processing of linguistic material. Inclusion of assessment of this defect might prove beneficial in determining the presence of dyslexia in young children at a younger age, and an earlier intervention could be initiated.
KeywordsDyslexia Eye movements Learning disabilities Reading disability
Conflict of interest
The authors have no financial or proprietary interest in any material or method mentioned.
The study was performed with informed consent.
- Fagerheim, T., Raeymaekers, P., Tonnessen, F. E., et al. (1999). A new gene (DYX3) for dyslexia is located on chromosome 2. Journal of Medical Genetics, 36, 664–669.Google Scholar
- Fischer, B., & Hartnegg, K. (2000). Stability of gaze control in dyslexia. Strabismus, 8, 119–122.Google Scholar
- Grigorenko, E. L., Wood, F. B., Meyer, M. S., et al. (1997). Susceptibility loci for distinct components of developmental dyslexia on chromosomes 6 and 15. American Journal of Human Genetics, 60, 27–39.Google Scholar
- McConkie, G. W., Zola, D., Grimes, J., Kerr, P. W., Bryant, N. R., & Wolff, P. M. (1991). Children’s eye movements during reading. In J. F. Stein (Ed.), Vision and visual dyslexia (pp. 251–270). London: Macmillan.Google Scholar
- Ober, J., Hajda, J., Loska, J., & Jamicki, M. (1997). Application of eye movement measuring system OBER 2 to medicine and technology. Proc SPIE 3061, Infrared Technology and Applications XXIII;327.Google Scholar
- Olson, R. K., Conners, F. A., & Rack, J. P. (1991). Eye movements in dyslexic and normal readers. In J. F. Stein (Ed.), Vision and visual dyslexia (pp. 243–250). London: Macmillan.Google Scholar
- Pavlidis, G. T. (1991). Diagnostic significance and relationship between dyslexia and erratic eye movements. In J. F. Stein (Ed.), Vision and visual dyslexia (pp. 263–270). CRC Press: Michigan.Google Scholar
- Sartori, G., Job, R., & Tressoldi, P. E. (2007). DDE-2. Batteria per la valutazionedelladislessia e delladisortografiaevolutiva (Battery for the assessment of developmental dyslexia and dysorthographia). Firenze: Giunti OS.Google Scholar
- Wechsler, D. (1991). WISC-III: Wechsler intelligence scale for children. New York: The Psychological Corporation.Google Scholar