Dyslexia and visual perception: is there a relation?

Opinions differ concerning the relation between dyslexia and visual perception. In this pilot study we addressed this question by analyzing the results of visual perceptual testing on 19 elementary grade subjects diagnosed as having dyseidesia, one type of dyslexia that manifests as problems with sight-word recognition. The subjects, who have different degrees of severity of dyseidesia, were compared with 11 subjects tested as nondyslexic, but with reading problems. The Dyslexia Determination Test (DDT) and the Test of Visual Perceptual Skills (TVPS) were given to all subjects. Both multivariate analysis of variance (MANOVA) and univariate one-way analysis of variance (ANOVA) to test for differences in performance among four test groups (ranging from nondyslexic to increasing levels of severity of dyseidesia) showed no trends of either statistical or clinical importance. An individual with reading problems may be nondyslexic but have poor visual perceptual skills, or may be dyslexic with good visual perceptual skills. These results are consistent with the contention that reading problems caused by dyseidesia (as defined by the DDT) and those caused by visual perceptual deficiencies (as defined by the TVPS) are different. Although dyseidetic dyslexia results in characteristic coding patterns producing specific reading problems, it is probable that visual perceptual deficiencies contribute to learning problems that include general reading problems. Each condition would, therefore, require different forms of therapy. Limitations of this study and recommendations for future research are discussed.