Techniques for Infants and Toddlers with Visual Impairment - Prevelance
Prevalence of Visual Impairment
by Alycyn Ferrell and Sharon A. Raver
Precise figures on the prevalence and incidence of visual impairment in infancy are also difficult to obtain. While P.L. 94-142 requires annual reports from states on the number of children being served, the count of visually handicapped children is generally thought to be inaccurate and to grossly undercount the number of children between the ages of birth and 21 years who are visually impaired (Huebner & Ferrell, 1986; Kirchner, 1989; Packer & Kirchner, 1985). The situation is further confused by the addition, in the late 1970’s, of deaf-blind and multiple handicapped categories in the schools’ annual county (Vaughn & School, 1980). Many visually handicapped children may, in fact, be counted in these new categories.
Kirchner (1989) thoroughly discusses the various data sources and their weaknesses, including the variability of definitions, methodologies, and age ranges used. She shows that the databases that include children younger than 5 years indicate a prevalence of visual impairment of 0.42 to 0.86 per 1.000 population. (Interestingly, the highest rate is reported by the American Printing House for the Blind, which uses the more restrictive definition of legal blindness). Whatever database is used, the population of infants with visual impairment who receive early intervention services is small.
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