Dyslexia and learning disabilities: an overview.

The concept and definition of dyslexia have been evolving for more than a century. Although it is certain that dyslexia is not a unitary syndrome, a comprehensive, testable definition has eluded us. Its characteristics have been differentially related to age; maturation of the brain and nervous system; auditory, visual, and intersensory processing; genetics; nutrition; and the environment. That we are dealing with an interdisciplinary disorder is beyond question. Optometrists do not treat dyslexia. They treat reading-disabled (RD) children who manifest some type of visual dysfunction that impairs their ability to respond to the specific instruction intended to remedy the disability. The papers in this Symposium are intended to provide a more precise understanding of the role of optometrists and other members of the interdisciplinary team in the management of dyslexic children.