Shahid Beheshti University of Medical Sciences The Scientific Journal of Rehabilitation Medicine 2251-8401 4 2 2015 06 22 An investigation of the contrast sensitivity in dyslexic children An investigation of the contrast sensitivity in dyslexic children 118 126 1100033 10.22037/jrm.2015.1100033 FA Monireh Feizabadi 1. Student Reseach Committee, MSc Student of Optometry, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Mohammad Aghazadeh Amiri 2. OD in Optometry, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 0000-0002-5532-4024 Mohammad Ghasemi Borumand 3. Professor of Ophthalmology, Faculty of Rehabilitation Sciences, Shahid Beheshti University of Medical Sciences, Tehran, Iran. 0000-0003-2372-3861 Marzieh Shiri Aminloo 4. MSc in Psychology and Education of Exceptional Children, Office of Special Education. Seyed Mehdi Tabatabaee 5. MSc in Biostatistics, Faculty of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran 0000-0002-6757-5795 Journal Article 2014 10 21 Background and Aim: A review of the neurophysiological studies suggests that dyslexia is the result of a deficit in the magnocellular part of the visual system. Most of the evidence cited in favour of this hypothesis is from contrast sensitivity studies. This study tested the hypothesis that visual processing deficits may be present in dyslexia by comparing the visual contrast sensitivity of dyslexic children and controls. <br />Materials and Methods: contrast thresholds were recorded in 67 children, 26 dyslexic (mean age of 8.76±1.33) and 41 control group (mean age 9.07±1.40). Contrast sensitivity was measured using Freiburg acuity and contrast test (FrACT) version 3.7 at frequency 5cpd in both eyes. The results were then analyzed using SPSS-18. <br />Results: mean contrast threshold of Right eyes in dyslexic group(0.62±0.12)and control group (0.68± 0.15), mean contrast threshold of Left eyes in dyslexic group (0.61±0.16) and control group (0.67±0.15) were measured. There were no statistically significant differences between two groups in ight eyes (pvalue: 0.279) and in left eyes (pvalue: 0.124). <br />Conclusion: The present study do not support the hypothesis of magnocellular visual pathway deficit in dyslexia. Our result show that there isn’t relationship between reading ability and contrast sensitivity in dyslexic children. Background and Aim: A review of the neurophysiological studies suggests that dyslexia is the result of a deficit in the magnocellular part of the visual system. Most of the evidence cited in favour of this hypothesis is from contrast sensitivity studies. This study tested the hypothesis that visual processing deficits may be present in dyslexia by comparing the visual contrast sensitivity of dyslexic children and controls. <br />Materials and Methods: contrast thresholds were recorded in 67 children, 26 dyslexic (mean age of 8.76±1.33) and 41 control group (mean age 9.07±1.40). Contrast sensitivity was measured using Freiburg acuity and contrast test (FrACT) version 3.7 at frequency 5cpd in both eyes. The results were then analyzed using SPSS-18. <br />Results: mean contrast threshold of Right eyes in dyslexic group(0.62±0.12)and control group (0.68± 0.15), mean contrast threshold of Left eyes in dyslexic group (0.61±0.16) and control group (0.67±0.15) were measured. There were no statistically significant differences between two groups in ight eyes (pvalue: 0.279) and in left eyes (pvalue: 0.124). <br />Conclusion: The present study do not support the hypothesis of magnocellular visual pathway deficit in dyslexia. Our result show that there isn’t relationship between reading ability and contrast sensitivity in dyslexic children. https://medrehab.sbmu.ac.ir/article_1100033_e0170bb51b87b498e8928a5b89598b47.pdf