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

Kapoula, Zoı̈; Ganem, Rebecca; Poncet, Sarah; Daunys, Gintautas; Eggert, Thomas; Brémond‐Gignac, Dominique; Bucci, Maria Pia

doi:10.1002/dys.377

Cited by 20 publications

(22 citation statements)

References 37 publications

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“…The invariance of the quality of binocular coordination with the condition is consistent with our previous study in normal young children (7 years old) and adults who showed similar binocular coordination in reading single words and in saccades to LEDs [13]. The present study suggests that binocular saccade disconjugacy is higher in dyslexics; this observation is further consolidated by another study from our group (Kapoula et al, submitted) [24] also examining saccades during free exploration of images. In the latter study, both age-matched and reading-matched comparisons are made.…”

Section: Discussionsupporting

confidence: 94%

Poor binocular coordination of saccades in dyslexic children

Bucci

Brémond‐Gignac

Kapoula

2007

Graefes Arch Clin Exp Ophthalmol

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108

104

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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.

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Section: Discussionsupporting

confidence: 94%

Poor binocular coordination of saccades in dyslexic children

Bucci

Brémond‐Gignac

Kapoula

2007

Graefes Arch Clin Exp Ophthalmol

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108

104

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“…This saccade disconjugacy was also found to be present during reading [15]. In dyslexic children, the saccade disconjugacy was found to be increased when compared with age-matched non-dyslexics in a single word reading task [6] and this observation held for free explorations of paintings [16]. Moreover, the saccade disconjugacy is typically followed by a disconjugate drift during the subsequent fixation, which passively restores the disconjugacy due to saccade, i.e., a pulse-slide-step activity recorded in abducens neurons [17].…”

Section: Introductionmentioning

confidence: 66%

“…However, such a pattern was not present in dyslexic children when performing a word reading task [6] or free image exploration [16]. It remains to be seen whether this holds for text reading as well.…”

Section: Introductionmentioning

confidence: 91%

Dyslexic Children Are Confronted with Unstable Binocular Fixation while Reading

Jainta

Kapoula

2011

PLoS ONE

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Reading requires three-dimensional motor control: saccades bring the eyes from left to right, fixating word after word; and oblique saccades bring the eyes to the next line of the text. The angle of vergence of the two optic axes should be adjusted to the depth of the book or screen and - most importantly - should be maintained in a sustained manner during saccades and fixations. Maintenance of vergence is important as it is a prerequisite for a single clear image of each word to be projected onto the fovea of the eyes. Deficits in the binocular control of saccades and of vergence in dyslexics have been reported previously but only for tasks using single targets. This study examines saccades and vergence control during real text reading. Thirteen dyslexic and seven non-dyslexic children read the French text “L'Allouette” in two viewing distances (40 cm vs. 100 cm), while binocular eye movements were measured with the Chronos Eye-tracking system. We found that the binocular yoking of reading saccades was poor in dyslexic children (relative to non-dyslexics) resulting in vergence errors; their disconjugate drift during fixations was not correlated with the disconjugacy during their saccades, causing considerable variability of vergence angle from fixation to fixation. Due to such poor oculomotor adjustments during reading, the overall fixation disparity was larger for dyslexic children, putting larger demand on their sensory fusion processes. Moreover, for dyslexics the standard deviation of fixation disparity was larger particularly when reading at near distance. We conclude that besides documented phoneme processing disorders, visual/ocular motor imperfections may exist in dyslexics that lead to fixation instability and thus, to instability of the letters or words during reading; such instability may perturb fusional processes and might – in part - complicate letter/word identification.

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“…Binocular vision disruption at earlier age affects the normal development of the child. It also hinders the learning process 20. Therefore, strabismus should be corrected by pediatric ophthalmologists and appropriate orthoptic management should be attempted.…”

Section: Discussionmentioning

confidence: 99%

Refractive error and visual functions in children with special needs compared with the first grade school students in Oman

Vora

Khandekar

Natrajan

et al. 2010

Middle East Afr J Ophthalmol

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Background:We evaluated the refractive status and visual function of children with special needs (other handicap) in 2010 and compared them with healthy 1st grade school students in Oman.Materials and Methods:This was a cohort study. Optometrists recorded vision using a logarithm of minimum angle of resolution (LogMAR) chart. Preferential looking method was used for testing 31 children. Cycloplegic refraction was performed on all children. Contrast sensitivity was tested using 2.5%, 10%, and 100% contrast charts. Ocular movement, alignment, and anterior segment were also assessed. A pediatrician reviewed the health records of all the children at the time of their enrollment in this study to determine if the child had been diagnosed with a systemic condition or syndromes. The visual functions were assessed by study investigators. We estimated the rates and the risk of different visual function defects in children with special needs.Result:The prevalence of refractive error in 70 children (4.7 ± 0.8 years) with special needs (group 1) and 175 normal healthy first grade students (group 2) were 58.5% and 2.9%, respectively. The risk of refractive error was significantly higher in children with special needs [relative risk, 48.1 (95% confidence interval, 17.54–131.8)]. Hyperopia (>1.00 D), myopia (≥ 1.00D) and astigmatism (≥ ±1.00 D) were found in 18.6%, 24.3%, and 27.1%, respectively, in group 1. Six children in this group had defective near vision. Sixteen (80%) children with Down syndrome had refractive error. Seven (50%) children with developmental disorder showed decreased contrast sensitivity.Conclusion:Prevalence of uncorrected refractive error was much higher in children with special needs. Prevalence of strabismus, nystagmus, and reduced contrast sensitivity was also higher in children with special needs. Early vision screening, visual function assessment, correction of refractive error, and frequent follow-up are recommended.

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

Cited by 20 publications

References 37 publications

Poor binocular coordination of saccades in dyslexic children

Poor binocular coordination of saccades in dyslexic children

Dyslexic Children Are Confronted with Unstable Binocular Fixation while Reading

Refractive error and visual functions in children with special needs compared with the first grade school students in Oman

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