Visual orientation in reading disability: diagnostic considerations.

Reading disability (also called reading retardation) is defined as a significant reduction in reading ability relative to general intelligence. Some defintions arbitrarily specify that reading be a certain number of years or academic grades (usually two) below the individual's general intellectual capacity. Other definitions involve a certain percentage of reduction below average reading ability. However, these arbitrary figures have not found universal acceptance and, in practice, the crucial factor is that the child's reading ability is so impaired that he is unable to function adequately in school. Since reading ability is low in relation to general intelligence, the definition excludes most mentally retarded children.