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True dyslexia is a neurological dysfunction marked by the inability of the brain's language centers to efficiently decode print or phonetically make the connection between written symbols and their appropriate sounds.  Not all children who struggle to read, however, suffer from phonological processing problems.  Although the symptoms are similar, the culprit for many may be vision, not a language-based deficit.  

Margaret Livingstone, et al, from the Department of Neurobiology, Harvard Medical School and the Dyslexia Research Laboratory, Beth Israel Hospital in Boston reports that poor visual processing plays a significant role in a large majority of children who struggle to read:   "Several perceptual studies have suggested that dyslexic subjects process visual information more slowly than normal subjects.  Such visual abnormalities were reported to be found in more than 75% of the reading-disabled children tested."  

A complete eye exam by a developmental optometrist trained to diagnose and treat vision-based learning problems can determine for certain if vision is the basis of a child's struggle to read. For more complete information on this topic, see our "Vision and Reading" page.  

Below is the position statement of the American Academy of Optometry and the American Optometric Association on the relationship between vision and dyslexia. Children who have been labeled "dyslexic" need to have a complete eye examination by a pediatric optometrist to evaluate their learning-related vision skills to determine to what degree poor visual processing is contributing to the problem.  For a specialist near you, contact the national certifying board of the College of Optometrists in Vision Development at 1-888-268-3770 or visit their web site at www.covd.org

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From America's Leaders in Eye Care:

Vision, Learning, and Dyslexia

A Joint Organizational Policy Statement of the American Academy of Optometry
 and the American Optometric Association
 

Vision and Learning

Many children and adults continue to struggle with learning in the classroom and the workplace. Advances in information technology, its expanding necessity, and its accessibility are placing greater demands on people for efficient learning and information processing. (1,2)  Learning is accomplished through complex and interrelated processes, one of which is vision. Determining the relationships between vision and learning involves more than evaluating eye health and visual acuity (clarity of sight). Problems in identifying and treating people with learning-related vision problems arise when such a limited definition of vision is employed. (3) This policy statement addresses these issues, which are important to individuals who have learning-related vision problems, their families, their teachers, the educational system and society.
 
 

Policy Statement

People at risk for learning-related vision problems should receive a comprehensive optometric evaluation. This evaluation should be conducted as part of a multidisciplinary approach in which all appropriate areas of function are evaluated and managed. (4)

The role of the optometrist when evaluating people for learning-related vision problems is to conduct a thorough assessment of eye health and visual functions and communicate the results and recommendations. (5) The management plan may include treatment, guidance and appropriate referral. The expected outcome of optometric intervention is an improvement in visual function with the alleviation of associated signs and symptoms. Optometric intervention for people with learning-related vision problems consists of lenses, prisms, and vision therapy. Vision therapy does not directly treat learning disabilities or dyslexia. (6,7) Vision therapy is a treatment to improve visual efficiency and visual processing, thereby allowing the person to be more responsive to educational instruction. (4,8) It does not preclude any other form of treatment and should be a part of a multidisciplinary approach to learning disabilities. (6,7)
 
 

Pertinent Issues

Vision is a fundamental factor in the learning process. The three interrelated areas of visual function are:

1.Visual pathway integrity including eye health, visual acuity and refractive status

2.Visual efficiency including accommodation (focusing), binocular vision (eye teaming) and eye movements

3.Visual information processing including identification and discrimination, spatial awareness, and integration with other senses.

To identify learning-related vision problems, each of these interrelated areas must be fully evaluated. Educational, neuropsychological and medical research has suggested distinct subtypes of learning difficulties. (9,10) Current research indicates that some people with reading difficulties have co-existing visual and language processing deficits. (11) For this reason, no single treatment, profession or discipline can be expected to adequately address all of their needs.

Unresolved visual deficits can impair the ability to respond fully to educational instruction. (12,13) Management may require optical correction, vision therapy, or a combination of both. Vision therapy, the art and science of developing and enhancing visual abilities and remediating vision dysfunctions, has a firm foundation in vision science, and both its application and efficacy have been established in the scientific literature. (14-17) Some sources have erroneously associated optometric vision therapy with controversial and unfounded therapies, and equate eye defects with visual dysfunctions. (18-21) The eyes, visual pathways and brain comprise the visual system. Therefore, to understand the complexities of visual function, one must look at the total visual system. Recent research has demonstrated that some people with reading disabilities have deficits in the transmission of information to the brain through a defective visual pathway. (22-25) This creates confusion and disrupts the normal visual timing functions in reading.

Visual defects, such as a restriction in the visual field, can have a substantial impact on reading performance. (26) Eye strain and double vision resulting from convergence insufficiency can be a significant handicap to learning. (27) There are more subtle visual defects that influence learning affecting different people to different degrees. Vision is a multifaceted process and its relationships to reading and learning are complex. (28,29) Each area of visual function must be considered in the evaluation of people who are experiencing reading or other learning problems. Likewise, treatment programs for learning-related vision problems must be designed individually to meet each person's unique needs.
 
 

Summary

1. Vision problems can and often do interfere with learning.

2. People at risk for learning-related vision problems should be evaluated by an optometrist who provides diagnostic and management services in this area.

3. The goal of optometric intervention is to improve visual function and alleviate associated signs and symptoms.

4. Prompt remediation of learning-related vision problems enhances the ability of children and adults to perform to their full potential.

5. People with learning problems require help from many disciplines to meet the learning challenges they face. Optometric involvement constitutes one aspect of the multidisciplinary management approach required to prepare the individual for lifelong learning.
 

This Policy Statement was formulated by a Task Force representing the College of Optometrists in Vision Development, the American Optometric Association, and the American Academy of Optometry. The following individuals are acknowledged for their contributions:

Ronald Bateman, O.D. M.S., Leonard Press, O.D., Susan Cotter, O.D., Michael Rouse, O.D., Stephen Miller, O.D. M.S.Ed., Kelly Frantz, O.D, Julie Ryan, O.D., Ralph Garzia, O.D., Eric Borsting, O.D., Glen Steele, O.D., Louis Hoffman, O.D.M.S., Gary Williams, O.D

Approved by:

College of Optometrists in Vision Development, October 1996

American Academy of Optometry, January 1997

American Foundation for Vision Awareness, February 1997

American Optometric Association, March 1997

Optometric Extension Program Foundation, April 1997

References

1.Kozol J. Illiterate America, 1st edition. Garden City, NY: Anchor Doubleday, 1985.
2.Anderson RC, et al. Becoming a Nation of Readers: The Report of the Commission on Reading. Washington, D.C.: The National Academy of Education/Institute of Education, 1984.
3.Flax N. General issues. In: Scheiman MM, Rouse MW (eds): Optometric Management of Learning-Related Vision Problems. St. Louis: C.V. Mosby, 1994:127-52.
4.Solan HA, Press LJ. Optometry and learning disabilities. J Optom Vision Dev 1989; 20:5-21.
5.Groffman S, Solan HA. Developmental and Perceptual Assessment of Learning-Disabled Children: Theoretical Concepts and Diagnostic Testing. Santa Ana,   CA: Optometric Extension Program, 1994.
6.Hoffman LG. The purpose and role of vision therapy. J Optom Vision Dev 1988; 19:1-2.
7.Getman GN. A commentary on vision training. J Learn Disabil 1985; 18:505-12.
8.Solan HA. Learning disabilities. In: Rosenbloom AA, Morgan MW (eds): Principles and Practice of Pediatric Optometry. Philadelphia: Lippincott, 1990:486-517.
9.Learning disabilities: Issues on definition. A position paper of the National Joint Committee on Learning Disabilities. J Learn Disabil 1987; 20:107-8.
10.Hooper SR, Willis WG. Learning Disability Subtyping: Neuropsychological Foundations, Conceptual Models, and Issues in Clinical Differentiation. New York: Springer-Verlag, 1989.
11.Eden GF, Stein JF, Wood MH, et al. Verbal and visual problems in reading disability. J Learn Disabil 1995; 28:272-90.
12.Flax N, Solan HA, Suchoff IB. Optometry and dyslexia. J Am Optom Assoc 1983; 54:593-4.
13.Helveston EM. Letter to the editor: Helveston's response to Solan. J Learn Disabil 1988; 21:586.
14.Hennessey D, Iosue RA, Rouse MW. Relation of symptoms to accommodative infacility in school-age children. Am J Optom Physiol Opt 1984; 61:177-83.
15.Simons HD, Grisham JD. Binocular anomalies and reading problems. J Am Optom Assoc 1987; 58:578-87.
16.Suchoff IB, Petito GT. The efficacy of visual therapy: accommodative disorders and non-strabismic anomalies of binocular vision. J Am Optom Assoc 1986; 57:119-25.
17.The 1986/87 Future of Visual Development/Performance Task Force. Special Report: The efficacy of optometric vision therapy. J Am Optom Assoc 1988; 59:95-105.
18.Ad Hoc Committee of the American Academy of Pediatrics, American Academy of Ophthalmology and Otolarygology, American Association of Ophthalmology. The eye and learning disabilities. Sightsav Rev 1971-72; 41:183-4.
19.American Academy of Ophthalmology. Policy Statement: Learning disabilities, dyslexia and vision. San Francisco, CA: American Academy of Ophthalmology, 1981.
20.American Academy of Ophthalmology. Policy Statement: Learning disabilities, dyslexia and vision. J Learn Disabil 1987; 20:412-3.
21.American Academy of Pediatrics Committee on Children with Disabilities, American Association for Pediatric Ophthalmology and Strabismus, American Academy of Ophthalmology. Learning disabilities, dyslexia and vision. Pediatrics 1992; 90:124-6.
22.Lhmkuhle S, Garzia RP, Turner L, et al. A defective visual pathway in children with reading disability.N Eng J Med 1993; 328:989-96.
23.Livingstone MS, Rosen GD, Drislane FW, et al. Physiological and anatomical evidence for a magnocellular defect in developmental dyslexia. Proc Natl Acad Sci USA 1991; 88:7943-7.
24.Lovegrove W, Martin G, Slaghuis W. A theoretical and experimental case for a visual deficit in specific reading disability. Cogn Neuropsychol 1986; 3:225-67.
25.Beitmeyer BG. Sustained (P) and transient (M) channels in vision: a review and implications for reading. In: Willows DM, Kruk RS, Corcos E (eds): Visual Processes in Reading and Reading Disabilities. Hillsdale: Lawrence Erlbaum; 1993:95-110.
26.McConkie GW, Rayner K. The span of the effective stimulus during a fixation in reading. Percept Psychophys 1975; 17:578-86.
27.Mazow ML, France TD, Finkelman S, et al. Acute accommodative and convergence insufficiency. Trans Am Ophthalmol Soc 1989; 87:158-73.
28.Willows DM. A framework for understanding learning difficulties and disabilities. In: Garzia RP (ed):Vision and Reading. St. Louis: C.V. Mosby, 1996:229-47.
29.Willows DM, Kruk RS, Corcos E. Are there differences between disabled and normal readers in their processing of visual information? In: Willows DM, Kruk RS, Corcos E (eds): Visual Processes in Reading and Reading Disabilities. Hillsdale: Lawrence Erlbaum, 1993:265-85.

 
 
Learn more about the connection between vision and reading!

 

 
 

The Children's Vision Information Network was created to raise public awareness about potential vision problems in children.  This site is not intended as a substitute for a complete eye exam and professional advice from your family optometrist.  Parents, teachers, occupational therapists, psychologists, and related professionals have permission to copy and distribute information contained in the site for educational purposes only with the condition that each page is copied in its entirety with the URL included (www.ChildrensVision.com).  All publishing rights are reserved. Direct specific inquiries to Mary Barton, Director of Vision Therapy, at (316) 722-3740 or email VTDirector@ChildrensVision.com.