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
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."
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.
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.
America's Leaders in Eye Care:
Learning, and Dyslexia
Joint Organizational Policy Statement of the American Academy of Optometry
American Optometric Association
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.
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)
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.
is a fundamental factor in the learning process. The three interrelated areas of
visual function are:
pathway integrity including eye health, visual acuity and refractive status
efficiency including accommodation (focusing), binocular vision (eye teaming)
and eye movements
information processing including identification and discrimination, spatial
awareness, and integration with other senses.
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
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.
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.
Vision problems can and often do interfere with learning.
People at risk for learning-related vision problems should be evaluated by an
optometrist who provides diagnostic and management services in this area.
The goal of optometric intervention is to improve visual function and alleviate
associated signs and symptoms.
Prompt remediation of learning-related vision problems enhances the ability of
children and adults to perform to their full potential.
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
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
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
of Optometrists in Vision Development, October 1996
Academy of Optometry, January 1997
Foundation for Vision Awareness, February 1997
Optometric Association, March 1997
Extension Program Foundation, April 1997
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,
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;
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
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
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;
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.
more about the connection between vision and reading!