For the purpose of special education eligibility, federal regulations define visual impairment (including blindness) as "an impairment in vision that, even with correction, adversely affects a child's educational performance" (34 C.F.R. Sec. 300.8(c)(13)). Some states have elaborated on this definition by specifying minimum levels of visual acuity or a restriction in the visual field. Thus, a child may qualify as having a visual impairment in one state, but may not qualify in another. Children and youth with visual impairments are fewer than 0.5 percent of those aged 6 through 21 who are served under Part B of the Individuals with Disabilities Education Act (IDEA) (U.S. Department of Education 2007a). Recent data indicate that about 12,000 youth aged 12 through 17 receive special education services nationwide because their primary disability is a visual impairment (U.S. Department of Education 2007b).
Some research suggests that the federal child count underestimates the incidence of visual impairment. For example, the number of children and youth with visual impairments reported to the American Printing House for the Blind is more than twice that reported to the federal government (Hueber 2000). The discrepancy can be explained by the IDEA requirement that children receiving special education services be reported under only one disability category. This means that children with visual impairments who have additional disabilities may be categorized as having multiple disabilities or reported in another disability category rather than visual impairment. Data on the prevalence of children with visual impairments who have additional disabilities are limited (Sacks and Silberman 1998), but one estimate is that 50 percent to 75 percent of the children with visual impairments have additional disabilities (Silberman 2000).
Students with visual impairments are served in a variety of educational settings, including regular public schools and public or private separate facilities (e.g., state-operated special schools, residential facilities, and hospitals). However, receiving instruction in separate facilities has become less common over time. For example, in 1950, 88 percent of children with visual impairments were educated in special schools, but in 1972, this figure had decreased to 32 percent (Lowenfeld 1981). Continuing this trend, 16 percent of students ages 12 through 17 who were served under IDEA Part B during the 1998-99 school year attended special schools (U.S. Department of Education 2001).
Regardless of setting, students with visual impairments "share one common characteristic—a visual restriction of sufficient severity that it interferes with normal progress in a regular educational program without some modifications" (Scholl 1986, p. 29). The level of severity has important implications for the degree of modification a student requires. In general, a child with low vision can usually be educated to some extent through his or her visual sense, whereas a child who is completely blind must be educated exclusively through tactile and other sensory channels. Thus, children and youth with visual impairments may receive a range of special education services, including training in orientation and mobility (Corn et al. 1995).