Fixation Preference and Grating Acuity in Strabismic Children

Abstract

Monocular visual acuity (VA) measurement is a useful part of pediatric ophthalmologic assessment. In the last three decades, different methods have been developed to provide this important information (Dobson & Teller, 1978; Marsh-Tootle, 1991; Fulton et al., 1993). Preferential looking (PL) is a behavioral method used in several experimental and clinical studies to quantify VA (Jacobson et al., 1982; Birch et al., 1990; Dobson et al., 1990). Information about amblyopia and visual deficit can be obtained by PL, comparing the results with normative data for VA development and interocular acuity differences, but there is some controversy about its value in the diagnosis of strabismic amblyopia (Ellis et al., 1988; Moskowitz et al., 1987; Moseley et al., 1986). Fixation preference is considered the most reliable clinical method to diagnose amblyopia in infants and non-verbal strabismic patients (Jacobson et al., 1982; Wright et al., 1986). Occlusion of one eye while the other is fixating a target is used to evaluate if the fixation behavior of that eye is central, steady and mantained.