Learning & Vision Research


Atzmon D, Nemet P, et al "A randomized prospective masked and matched comparative study of orthoptic/vision therapy treatment versus conventional reading tutoring treatment for reading disabilities in 62 children." Binoc Vision & Eye Muscle Surgery Qtrly, (8):91-106, 1993 

     Abstract:  Controversies remain whether orthoptics and/or visual therapy can remedy reading disabilities.  therefore, and to extend our prior studies, we under took a comparative and controlled study.  One hundred and twendty children with reading disability were tested extensively, matched and randomly divided into three groups: orthoptic, conventional reading tutoring and no treatment contol.  Unfortunately participants in the control group were unable to adhere to no treatment and were deleted.  Each of the 40 children in the first two groups had 40 sessions, 20 minutes daily.

     Vision therapy was directed to markedly increasing fusional convergence amplitudes for both near and distance to 60 diopters.  The two treatments were also carefully matched in time and effort.  Sixty two children in 31 matched pairs completed the course of treatment and testing.  The results were equal and statistically significant (p<.05) marked improvement in reading performance in both treatment groups on essentially all tests.

     Vision therapy is as effective as conventional in school reading tutoring treatment of reading disabilities.  An advantage of vision therapy was that subjective reading and asthenopic symptoms (excessing tearing, itching, burning, visual fatigue and headache) virtually disappeared after vision therapy.  We recommend vision therapy as 1) an effective alternate primary treatment; 2) adjunctive treatment for those who do not respond well to standard treatment; and 3) as primary treatment in any case with asthenopic symptoms of convergence inadequacy. 

Letter regarding the study above:


Dr. Firmon E. Hardenbergh, Chief of Ophthalmology and Ophthalmologist to the Harvard University Health Services wrote a letter on March 29, 1991 regarding orthoptic treatment and convergence insufficiency. This letter appeared in the journal of Binocular Vision and Eye Muscle Surgery Quarterly in the Spring of 1993.
"I have reviewed the report by Daniela Atzmon and Professor P. Nemet on the subject of the results of a study on the effect of orthoptic exercises on the academic performance of learning/reading disabled children with convergence insufficiency. In my opinion, this prospective study was well planned and is essentially double blinded since the reading testing was not administered by either the tutors or the orthoptists.
The results support the proposition that application of orthoptics to all learning/reading disabled or deficient children who manifest convergence insufficiency should be the first line of therapy. If reading ability does not improve significantly within four to six months, other interventions should then be instituted.

Brysbaert, Dr. Marc and Vitu, Dr. Francoise.(1998) "Word skipping: Implications for theories of eye movement control in reading." in Underwood, Prof. G., Eds., "Eye Guidance in Reading and Scene Perception" pages pp. 125-147.
    This chapter provides a meta-analysis of the factors that govern word skipping in reading.  It is concluded that the primary predictor is the length of the word to be skipped. A much smaller effect is due to the processing ease of the word (e.g., the frequency of the word and its predictability in the sentence).
Chaparro A, Young RS, "Reading with rods: the superiority of central vision for rapid reading."  Invest. Ophthalmol. Vis. Sci. 1993 34: 2341-2347.
   Purpose: To investigate why the central portion of the visual field is normally the optimal region for pattern recognition.
   Method: The study uses a reading paradigm in which the text can only be seen with rod vision. Reading rates were measured as the text was positioned in different parts of the visual field. 
   Results: Observers obtained the highest reading rates when rod-generated images were viewed at or near the fovea.
   Conclusion: The superiority of the central field for reading is neither linked to some exclusive property of the cone visual system, nor is it primarily related to visual sensitivity or spatiotemporal resolution. The superiority of reading in the central field is associated with some aspect of the visual cortical processes.


COVD. "A summary of research and clinical studies on vision and learning."

    A listing of some of the research reports and clinical studies on the relationship of vision to reading and learning ability and the effectiveness of vision therapy in the treatment of learning related vision problems is provided.


Dusek W., Pierscionek B., McClelland J. "A survey of visual function in an Austrian population of school-age children with reading and writing difficulties."  BMC Ophthalmology 2010, 10:16.

      Background: To describe and compare visual function measures of two groups of school age children (6-14 years of age) attending a specialist eyecare practice in Austria; one group referred to the practice from educational assessment centres diagnosed with reading and writing difficulties and the other, a clinical age-matched control group.

      Methods: Retrospective clinical data from one group of subjects with reading difficulties (n = 825) and a clinical control group of subjects (n = 328) were examined.  Statistical analysis was performed to determine whether any differences existed between visual function measures from each group (refractive error, visual acuity, binocular status, accommodative function and reading speed and accuracy).

      Results: Statistical analysis using one way ANOVA demonstrated no differences between the two groups in terms of refractive error and the size or direction of heterophoria at distance (p > 0.05). Using predominately one way ANOVA and chi-square analyses, those subjects in the referred group were statistically more likely to have poorer distance visual acuity, an exophoric deviation at near, a lower amplitude of accommodation, reduced accommodative facility, reduced vergence facility, a reduced near point of convergence, a lower AC/A ratio and a slower reading speed than those in the clinical control group (p < 0.05).

      Conclusions: This study highlights the high proportions of visual function anomalies in a group of children with

 reading difficulties in an Austrian population. It confirms the importance of a full assessment of binocular visual status in order to detect and remedy these deficits in order to prevent the visual problems continuing to impact upon educational development.

Eden GF, Stein JF, Wood HM, Wood FB, "Differences in eye movements and reading problems in dyslexic and normal children."  Vision Research 1994 May; 34(10):1345-58.
    It has been suggested that eye movement abnormalities seen in dyslexics are attributable to their language problems.  In order to investigate this claim, we studied eye movements in dyslexic children, during several non-reading tasks. Dyslexic children were compared to normal and backward readers on measures of fixation, vergence amplitude, saccade and smooth pursuit.  The results were compared to the children's phonological ability.  Dyslexic children (n = 26) had significantly worse eye movement stability during fixation of small targets than normal children (n = 39). Vergence amplitudes were lower for dyslexics than for controls.  A qualitative assessment of saccadic eye movements revealed that dyslexics exhibit fixation instability at the end of saccades. Assessment of smooth pursuit revealed poor smooth pursuit in the dyslexic group, particularly when pursuing a target moving from left to right. Dyslexic children also performed significantly worse than normal children on a test of phonological awareness (Pig Latin). 
    Eye movement results were studied in the light of the findings on phonological awareness: dyslexics with small vergence amplitudes also always have poor phonemic awareness.  However, poor fixation control is found in dyslexics with or without poor phonological ability.  The backward reading children performed similar to the dyslexics on all tests, suggesting that the deficiencies observed in this study are not specific to children with dyslexia.  The problems experienced by the children (revealed by a questionnaire) are in agreement with those measured in terms of eye movement recordings and phonemic awareness.  Sex, handedness, IQ or the presence of attention deficit disorder (ADD) did not appear to influence the children's performances on any of the eye movement tasks. The presence of oculomotor abnormalities in a non-reading task strongly suggests that the underlying deficit in the control of eye movements seen in dyslexics is not caused by language problems alone.
Eden GF, Stein JF, Wood MH, Wood FB, "Verbal and visual problems in reading disability."  J Learn Disabil 1995 May; 28(5):272-90.
    Most individuals interested in reading disability favor the view that disordered language processing is the main cause of children's reading problems and that visual problems are seldom, if ever, responsible. Nevertheless, in a preliminary study (Eden, Stein, & Wood, 1993) we showed that visuospatial and oculomotor tests can be used to differentiate children with reading disabilities from nondisabled children. In the present study we investigated a larger sample of children to see if these findings held true. Using 93 children from the Bowman Gray Learning Disability Project (mean age = 11.3 years; 54 boys, 39 girls), we compared the phonological and visuospatial abilities of nondisabled children (children whose reading at fifth grade rated a Woodcock-Johnson reading standardized score between 85 and 115), and children with reading disability (whose reading standardized score was below 85 on the Woodcock-Johnson). In addition to performing poorly on verbal tests, the children with reading disability were significantly worse than nondisabled children at many visual and eye-movement tasks. A high proportion of the variance (68%) in reading ability of both the nondisabled children and those with reading disability could be predicted by combining visual and phonological scores in a multiple regression. These results provide further support for the hypothesis that reading disability may, to some extent, result from dysfunction of the visual and oculomotor systems.
Fischer B, Hartnegg K, "Effect of visual training on saccade control in dyslexia."  Perception, 29(5):531-542, 2000
    Abstract:  This study reports the effects of daily practice of three visual tasks on the saccadic performance of 85 dyslexic children in the age range of 8 to 15 years.  The children were selected from among other dyslexics because they showed deficits in their eye movement control, especially in fixation stability and/or voluntary saccade control.  Their eye movements were measured in an overlap prosaccade and a gap antisaccade task before and after the training.  the three tasks used for the training included a fixation, a saccade, and a distractor condition.  In any of these tasks, the subject had to detect the last orientation of a small pattern that rapidly changed its orientation between up, down, right, and left, before it disappeared after some time.  The task was to press one of four keys corresponding to the last orientation.  The visual pattern was presented on an LCD display of a small hand-held instrument given to the children for daily use at home.  The results indicate that daily practice improved not only the perceptual capacity, but also the voluntary saccade control, within 3 to 8 weeks.  After the training, the group of dyslexics was no longer statistically different from the control group.
Fischer B, Hartnegg K, "Saccade control in dyslexia: Development, deficits, training and transer to reading."  Optometry & Vision Development, 39(4):181-190, 2008
   Background:  Saccade contorl is a complex function of our brain and reliex on the coordination of several subcortical, cortical and functional areas.  In the past it has been difficult to use data frmo saccade analysis as an additional diagnostic tool for insight into any particular patient's oculo-visual problem.  With the development of technological advances and optomotor research there is now a better understanding of visually guided saccadic reactiosn.  This article describes the development of saccade control, diagnostic data from dyslexic subjects, and its transfer to reading skills.  
   Methods:  All subjects were recruited from local schools.  Several standard tests (reading, spelling, intelligence) were used for inclusion/exclusion of the subjects participating in the various studies.  Eye movements were recorded by infrared light reflection methods.  Prosaccades with overlap conditions and antisaccades with gap conditions were required in 200 trials for each task.  Variables characterizing pro- and antisaccade performance were extracted for each subject.  Mean values and standard deviations comparing the experimental and control subjects were calculated in each of the 4 age groups in an age range of 7 to 17 years.  ANOVAs or t-test were used for statistical evaluations. 


Doman RJ, "The importance of visual pursuits and convergence."  J Nat Acad Child Devel 1984, Volume 4, No. 4.
    Visual development and reading comprehension problems in children can be caused by poor visual pursuits or the lack of coordination of eye movement while reading, and poor convergence, which is the inability of the eyes to focus on an object.  While children normally develop convergence skills during the creeping stage, both poor visual pursuit and lingering convergence problems can be treated through a number of specific exercises.

    Two eye movement experiments were conducted to investigate whether the morphological constituents of a prefixed word influenced early word processing when English was read. Participants read sentences containing free-stem, bound-stem, or pseudoprefixed words, and the availability of the prefixed word morphemes in the parafovea was manipulated. Although preview benefit was greatest for the entire word, there was evidence that subsequent word processing was facilitated in both the prefix-only and the stem-only conditions. This effect was not influenced by word type. There was no evidence that morphological preprocessing occurred when morphological information was available in the parafovea. In addition, reading times for the target word did not differ for the different word types. Thus, there was no evidence to suggest that morphological constituents influence early word processing during reading. It is possible that morphological effects tend to be obscured when examined within a sentence context (although this phenomenon may be specific to English).

Kambe G.  "Parafoveal processing of prefixed words during eye fixations in reading: evidence against morphological influences on parafoveal preprocessing."  Percept Psychophys. 2004 Feb;66(2):279-92.
   Two eye movement experiments were conducted to investigate whether the morphological constituents of a prefixed word influenced early word processing when English was read.  Participants read sentences containing free-stem, bound-stem or pseudoprefixed words and the availability of the prefixed word morphemes in the parafovea was manipulated.  Although preview benefit was greatest for the entire word, there was evidence that subsequent word processing was facilitated in bothe the prefix-only and the stem-only conditions.  This effect was not influenced by word type.  There was no evidence that morphological preprocessing occurred when morphological information was available in the parafovea.  In addition, reading times for the target word did not differ for the different word types.  Thus, there was no evidence to sugggest that morphological constituents influence early word processing during reading.


Kulp MT, Schmidt PP  "Effect of oculomotor and other visual skills on reading performance."  Optom Visual Sci, 1996 (73): 283-292
    Efficient reading requires accurate eye movements and continuous integration of information obtained from each fixation by the brain. Reading skill and oculomotor efficiency are related, and oculomotor deficiencies can be treated successfully with vision therapy.
Munoz DP, Armstrong IT, Hampton KA and Moore KD, "Altered Control of Visual Fixation and Saccadic Eye Movements in Attention-Deficit Hyperactivity Disorder." J Neurophysiol, 2003 (90): 503-514
    Attention-deficit hyperactivity disorder (ADHD) is characterized by the overt symptoms of impulsiveness, hyperactivity, and inattention.  A frontostriatal pathophysiology has been hypothesized to produce these symptoms and lead to reduced ability to inhibit unnecessary or inappropriate behavioral responses.  Oculomotor tasks can be designed to probe the ability of subjects to generate or inhibit reflexive and voluntary responses.  Because regions of the frontal cortex and basal ganglia have been identified in the control of voluntary responses and saccadic suppression, we hypothesized that children and adults diagnosed with ADHD may have specific difficulties in oculomotor tasks requiring the suppression of reflexive or unwanted saccadic eye movements.  To test this hypothesis, we measured eye movement performance in pro- and anti-saccade tasks of 114 ADHD and 180 control participants ranging in age from 6 to 59 yr.  In the pro-saccade task, participants were instructed to look from a central fixation point toward an eccentric visual target.  In the anti-saccade task, stimulus presentation was identical, but participants were instructed to suppress the saccade to the stimulus and instead look from the central fixation point to the side opposite the target.  The state of fixation was manipulated by presenting the target either when the central fixation point was illuminated (overlap condition) or at some time after it disappeared (gap condition).  In the pro-saccade task, ADHD participants had longer reaction times, greater intra-subject variance, and their saccades had reduced peak velocities and increased durations.  In the anti-saccade task, ADHD participants had greater difficulty suppressing reflexive pro-saccades toward the eccentric target, increased reaction times for correct anti-saccades, and greater intra-subject variance.  In a third task requiring prolonged fixation, ADHD participants generated more intrusive saccades during periods when they were required to maintain steady fixation.  The results suggest that ADHD participants have reduced ability to suppress unwanted saccades and control their fixation behavior voluntarily, a finding that is consistent with a fronto-striatal pathophysiology.  The findings are discussed in the context of recent neurophysiological data from nonhuman primates that have identified important control signals for saccade suppression that emanate from frontostriatal circuits.
Pavlidis GT, Teflioudi A. "Do ophthalmokinesis and reading develop in parallel?"  European Conference on Eye Movements 10, Utrecht University, The Netherlands, Sept 1999
    This study investigated the relationship between eye movements development and reading performance in Primary school children (7 - 9 y).   Eye movements are the best reflectors of reading performance, as reading and eye movements development follow parallel paths and usually one can be predicted from the other. Eye movement characteristics correlate highly with reading skill and, therefore, provide a reliable, and objective method for the evaluation of reading efficiency and for the diagnosis of reading and attentional difficulties.  Reading skills develop gradually, improving in precision and speed over the first 2 - 3 years of schooling and are clearly reflected in the pattern and characteristics of the reader's eye movements.  About two-thirds of the total development of readers' eye movements, occurring between the first grade and college level, is reported to be achieved by the 9th year of age.  The number of fixations is a better index of reading skills than the duration of fixations.
     Methodology: The subjects for this study were 120 first, second and third grade pupils taken from 3 public primary schools from the city of Thessaloniki, Greece. Their age ranged from 7 to 9 years of age and they represented the whole reading spectrum. The fully automated portable infrared OKG® photoelectric system developed by Prof. Pavlidis was used for automated eye movement data collection and analysis. All recordings took place at the schools we visited.  They were tested for their cognitive and their reading-writing abilities using the following tests:
       1) Raven.
       2) Word Recognition Reading tests, three texts (two appropriate for their grade and one two grades above.)
       3) Single Word Writing tests, three texts (same as in Reading).
       4) Eye Movements recording during reading and non-reading tasks (Pavlidis Test).
    Reading tasks: The children's saccadic and pursuit eye movements were recorded while they read on the monitor the above mentioned texts. Their comprehension, speed and accuracy of reading were analyzed.
    Non-reading tasks: While the children follow with their eyes sequentially illuminated light spots or a slowly moving light spot on a computer monitor, their eye movements were synchronously recorded. These tasks are independent of any linguistic, high level information processing requirements and are not influenced by memory, emotional factors or intelligence. The saccadic task simulated the reading process by replacing words with simultaneously and equidistantly presented light spots. 
    Results: The results show a high degree of correlation between ophthalmokinesis and reading performance.
Rayner K. "Eye movements and attention in reading, scene perception, and visual search."  Q J Exp Psychol (Colchester). 2009 Aug;62(8):1457-506. Epub 2009 May 14.
   Eye movements are now widely used to investigate cognitive processes during reading, scene perception, and visual search. In this article, research on the following topics is reviewed with respect to reading: (a) the perceptual span (or span of effective vision), (b) preview benefit, (c) eye movement control, and (d) models of eye movements. Related issues with respect to eye movements during scene perception and visual search are also reviewed. It is argued that research on eye movements during reading has been somewhat advanced over research on eye movements in scene perception and visual search and that some of the paradigms developed to study reading should be more widely adopted in the study of scene perception and visual search. Research dealing with "real-world" tasks and research utilizing the visual-world paradigm are also briefly discussed.


Rayner K, Castelhano MS, Yang J.  "Eye movements and the perceptual span in older and younger readers."  Psychol Aging, 2009 Sept; 24(3): 755-60
   The size of the perceptual span (or the span of effective vision) in older readers was examined with the moving window paradigm (G. W. McConkie & K. Rayner, 1975). Two experiments demonstrated that older readers have a smaller and more symmetric span than that of younger readers. These 2 characteristics (smaller and more symmetric span) of older readers may be a consequence of their less efficient processing of nonfoveal information, which results in a riskier reading strategy.
Reichle ED, Rayner K, Pollatsek A.  "The E-Z reader model of eye-movement control in reading: comparisons to other models."  Behav Brain Sci. 2003 Aug;26(4):445-76; discussion 477-526

    The E-Z Reader model (Reichle et al. 1998; 1999) provides a theoretical framework for understanding how word identification, visual processing, attention, and oculomotor control jointly determine when and where the eyes move during reading. In this article, we first review what is known about eye movements during reading. Then we provide an updated version of the model (E-Z Reader 7) and describe how it accounts for basic findings about eye movement control in reading. We then review several alternative models of eye movement control in reading, discussing both their core assumptions and their theoretical scope. On the basis of this discussion, we conclude that E-Z Reader provides the most comprehensive account of eye movement control during reading. Finally, we provide a brief overview of what is known about the neural systems that support the various components of reading, and suggest how the cognitive constructs of our model might map onto this neural architecture.
Rounds BB, Manley CW, Norris RH  "The effect of oculomotor training on reading efficiency." J Amer Optom Assoc, 1991 (62): 92-97 

    Optometric vision therapy improved the reading efficiency of 10 adult "poor readers" who had failed an academically appropriate reading test, compared to a control group that did not receive therapy.  The purpose of this study was to record and measure, by means of a microcomputer, the reading eye movements and reading efficiency of a sample of poor readers from an adult, professional school population. A program of oculomotor enhancement training (vision therapy) was given to 10 students who failed an academically appropriate reading test. Their pre- and post- training reading performance was compared to that of a group of students who also failed the reading test but received no such training. All subjects' eye movements were monitored and recorded individually while reading, using a Visagraph Eye-Movement Recording System. The subjects were split into an experimental group (receiving training) and a control group (receiving no training).  Following a 12-hour program of in-office and home training, the group receiving oculomotor training showed trends toward improved reading eye movement efficiency (number of regressions, number of fixations and span of recognition), compared to that of the untrained group.
Shin H, Park S, Park C. "Relationship between accommodative and vergence dysfunctions and academic achievement for primary school children."  Ophthamlic and Physiological Optics, 29 (6): 615-24.
     The purpose of this study was to investigate the prevalence and types of non-strabismic accommodative and/or vergence dysfunctions in primary school children, and to determine the relationship of these dysfunctions to academic achievement. A total of 1031 parents and their children aged 9-13 years responded to the College of Optometrists in Vision Development Quality of Life (COVD-QOL) questionnaire. Of these, 258 children whose visual symptom scores were e20 were identified for further evaluation. Comprehensive eye and vision examinations were provided to the children who met the eligibility criteria (114 of 258): eligible symptomatic children were those without amblyopia, strabismus, ocular and systemic pathology, and contact lens wear. Children were also excluded if they had visual acuity poorer than 20/25 in either eye or vertical phoria >1 prism diopter.
     The results showed that 82 of 114 (71.9%) of criteria-eligible symptomatic primary school children had non-strabismic accommodative and/or vergence dysfunctions. In addition, a significant relationship was found between these dysfunctions and academic scores in every academic area (reading, mathematics, social science and science) in the total sample. Therefore, accommodative and vergence functions should be tested for all school children who have visual symptoms and/or academic difficulties. Additional study is needed to determine if improvements of accommodative and vergence functions also improve academic achievement.

Solan HA, Shelley-Trembley J, Ficarra A, Silverman M, Larson S. "Role of Visual Attention in Cognitive Control of Oculomotor Readiness in Students with Reading Disabilities."  Journal of Learning Disabilities, Vol. 34, No. 2, 107-118 (2001)
     Abstract:  This study investigated eye movement and comprehension therapy in Grade 6 children with reading disabilities (RD). Both order of therapy and type of therapy were examined. Furthermore, the implications of visual attention in ameliorating reading disability are discussed. Thirty-one students with RD were identified using standardized reading comprehension tests. Eye movements were analyzed objectively using an infra-red recording device. Reading scores of participating children were 0.5 to 1 SD below the national mean. Testing took place before the start of therapy (T1) and was repeated after 12 weeks (T2) and 24 weeks (T3) of therapy. One group of students had eye movement therapy first, followed by comprehension therapy; in the other group, the order was reversed. Data were evaluated using a repeated measures MANOVA and post hoc tests. At T1, mean reading grade was 2 years below grade level, and eye movement scores were at about Grade 2 level. Mean growth in reading comprehension for the total sample was 2.6 years (p < .01) at T3; equally significant improvement was measured in eye movements (p < .01). Learning rate in reading comprehension improved from 60% (T1) to 400% (T3). Although within-group differences were statistically significant, between-group differences were not significant for comprehension or eye movements. Order of therapy (comprehension first or eye movements first) was not significant. Improvements in within-group scores for comprehension and eye movements were consistently significant at T2 and T3. Eye movement therapy improved eye movements and also resulted in significant gains in reading comprehension. Comprehension therapy likewise produced improvement both in eye movement efficiency and in reading comprehension. The results support the notion of a cognitive link among visual attention, oculomotor readiness, and reading comprehension.

Trudell, R.  "Research and clinical studies on vision, learning and optometric vision therapy (OVT)"

    This paper presents over 350 abstracts from 77 different journals within education, optometry, ophthalmology, neurology and psychology fields of study.  All works found relating to vision and learning are included - even those that purport to show little to no relationship between vision and learning.  Of the many summaries related to vision and learning reviewed here, only fifteen(15) concluded that vision was not related to learning.   


Vergilino-Perez D, Collins T, Dore-Mazars K.  "Decision and metrics of refixations in reading isolated words."  Vision Res. 2004 Aug; 44(17):2009-17
    Eye movements were recorded during the reading of long words presented in isolation. Overall, the decision to refixate was found to depend on both length and frequency of the word, while refixation amplitude depended only on word length. This finding corroborates the assumption that most refixation saccades are preplanned on the basis of the parafoveal word length. However, cancellation of such a plan is possible and could be linked to the lexical processing during the first fixation into the word. Finally, a small proportion of refixations are corrective saccades, related to an oculomotor error. Theoretical implications for models of eye movement control during reading are discussed.