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Strabismus ("crossed eyes") has been reported to be markedly elevated in individuals with autism. This article presents the findings from two studies of strabismus in autism. A clinical optometric examination of 34 individuals with autism, ages 7 to 19 years, found a strabismus rate of 50% (65% with exotropia and 35% with esotropia). A parent survey of 7,640 families found a reported incidence of 20% (18% in boys, 29% in girls). As strabismus occurs in only 2% to 4% of the general population, both studies reported here confirm the high rate of strabismus in autism. A number of concomitants of strabismus, derived from questionnaire data, are reported.
Strabismus, commonly referred to as "cross-eyedness," is a visual dysfunction in which one or both eyes are turned inward (esotropia) or outward (exotropia). Strabismus is readily detected and has been studied in many populations (Greenwald, 1979; Hoffman, Cohen, Feurer, & Klayman, 1970; Kaakinen, 1981; Ludlam, 1965). However, although visual abnormalities are common in individuals with autism (Kaplan, 1994; Ritvo et al., 1988; Rosenhall, Johansson, & Gillberg, 1988; Scharre & Creedon, 1992), strabismus has received little attention in the autism literature. Many of the symptoms that characterize autism, such as odd body posturing, gaze aversion, preference for peripheral vision, and visual "stimming," may be attributed to faulty vision (Kaplan, 1994; Kaplan, Carmody, & Gaydos,1996). This article investigates the incidence of strabismus in two samples of individuals with autism and reports certain concomitants of strabismus.
When the eyes do not align on the same point or position in space, the two images-one from each eye-do not converge. Consequently, these images do not form an integrated, composite image of the environment. Strabismus interferes with the dynamic process by which information is obtained about one's surroundings. Strabismus disrupts the development of binocular (3-dimensional) vision; thus, the affected person will likely have difficulty exploring and learning from his or her surroundings (Caloroso & Cotter, 1995; Kavner, 1985). Common problems associated with strabismus in the nonautistic, nonimpaired population include visual orientation, movement in space, balance, and learning (Caloroso & Cotter, 1995; Kavner, 1985).
The prevalence of strabismus in the nondisabled population is estimated to be between 2% and 4% (Ehrlich, 1983; Reinecke, 1979; Simons & Reinecke, 1978). Two published studies have reported relatively...