Evidence for frequent divergence impairment in French dyslexic children: deficit of convergence relaxation or of divergence per se?

Kapoula, Zoı̈; Bucci, Maria Pia; Jurion, Frederic; Ayoun, Julie; Afkhami, Farzaneh; Brémond‐Gignac, Dominique

doi:10.1007/s00417-006-0490-4

Cited by 42 publications

(55 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Visual acuity was normal (X 9 10 ), the near point of convergence was in the normal range (o6 cm), but the divergence capabilities measured by orthoptic tests (bar of prisms and cover test) at near were limited for many of the dyslexic children (mean7SD: 1072 prism diopters, the normal value being 17-25 prism diopters). The observation of frequent abnormalities in orthoptic tests in dyslexia has previously been reported by Fowler and Stein (1980) and Evans and Drasdo (1990) and recently confirmed in a large population by our group (see Kapoula et al, 2007).…”

Section: Participantssupporting

confidence: 67%

“…Moreover, we reported that orthoptic training of vergence improves binocular coordination of saccades in such children . Kapoula et al (2007) has observed increased incidence of vergence problems in dyslexic children. The possible relationship between vergence control and poor saccade binocular coordination in dyslexics needs further investigation.…”

Section: Clinical Considerationsmentioning

confidence: 98%

See 1 more Smart Citation

Free exploration of painting uncovers particularly loose yoking of saccades in dyslexics

et al. 2008

Self Cite

View full text Add to dashboard Cite

Binocular yoking of saccades is essential for single vision of words during reading. This study examines the quality of binocular coordination in individuals with dyslexia, independent of the process of reading. Fifteen dyslexia children (11.271.4 years) and 15 non-dyslexia individuals (8 children, aged 11.171.3 years, and 7 adults, 2473 years) were studied. Eye movements were recorded in two conditions. In the control condition, participants made saccades to a single target where the saccade direction and magnitude were controlled. In the experimental condition saccades were allowed to move freely while viewing paintings. The results indicated that, compared with the non-dyslexia group, the dyslexia group showed a larger saccade amplitude difference between the two eyes, as well as a larger conjugate post-saccadic drift, during painting exploration than that for saccades to a single target. While both groups showed a larger disconjugate post-saccadic drift during painting exploration relative to the control condition, this showed a negative correlation with saccade disconjugacy (i.e. disconjugate drift reduced the disparity) only for the non-dyslexia group. These results indicate that individuals with dyslexia have problems of binocular coordination, both during the saccade and fixations, which are independent of the reading process. It is suggested that

show abstract

Section: Participantssupporting

confidence: 67%

Section: Clinical Considerationsmentioning

confidence: 98%

Free exploration of painting uncovers particularly loose yoking of saccades in dyslexics

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…In summary, orthoptic evaluation showed a tendency of poor divergence in dyslexic children in line with another study on a larger population of dyslexic and non-dyslexic children [22].…”

Section: Orthoptic Testsmentioning

confidence: 65%

Poor binocular coordination of saccades in dyslexic children

Bucci

Brémond‐Gignac

Kapoula

2007

Graefes Arch Clin Exp Ophthalmol

Self Cite

102

104

View full text Add to dashboard Cite

Poor quality of binocular coordination of saccades and drift of the eyes after the saccade, regardless of the task, indicates an intrinsic ocular motor deficiency. Such a deficiency could be related to immaturity of the normal ocular motor learning mechanisms via which ocular motor coordination and stable fixation are achieved. Learning could be based on the interaction between the saccade and vergence subsystems. The cerebellum, but also cortical areas of the magnocellular stream such as the parietal cortex, could be the sites of ocular motor learning.

show abstract

“…Moreover, primary-school-age poor readers without dyslexia show worse binocular horizontal scanning, as assessed by the Developmental Eye Movement (DEM) test, related to a slower reading speed than their normal-reading peers [14]. Another study detected a divergence deficit per se independent of convergence and accommodation relaxation in French children with dyslexia [15]. These authors suggested that the fragility of vergence control is also associated with symptoms of visual fatigue and loss of attention and interest.…”

Section: Introductionmentioning

confidence: 94%