SCREENING FOR ANISOMETROPIA IN PRESCHOOL-CHILDREN

Purpose. A preschool vision screening program was reviewed to evaluate eccentric photoscreening (EP), visual acuity, and stereopsis in ident ifying anisometropia, Methods. Patients referred by the screening were examined to assess efficacy of the three screening techniques in a po pulation of preschool children. Testability and comparison of screenin g results to the classification of anisometropia (greater than or equa l to 1 D) by retinoscopy obtained during a complete examination were e valuated. Results. Although EP identified 94.5% of the anisometropic c hildren as abnormal, only 27.8% were classified as anisometropic by EP . Of the anisometropic children, 36.1% failed acuity, but only 19.4% f ailed based on a 2 line or greater interocular acuity difference. Ster eopsis correctly identified only 7.3% of anisometropes as abnormal. Co nclusions. The sensitivity of EP in identifying anisometropic children as abnormal was superior to acuity and stereopsis, yet its ability to identify anisometropia specifically was poor. Anisometropia of low ma gnitude or that masked by the dead zone of the EP system was frequentl y classified as isometropic. Altering the EP referral criterion and/or taking photographs through adequate power plus lenses may improve the sensitivity for specifically identifying anisometropia, However, caut ion must be exercised when using EP to examine the prevalence of aniso metropia in a population or if used to screen for only amblyogenic ref ractive errors (i.e., anisometropia), because many anisometropes will be missed, resulting in inaccurate prevalence data and significant und erreferrals.