Early screening for amblyogenic risk factors lowers the prevalence and severity of amblyopia

Purpose: To evaluate the efficacy of a mass screening program for amblyopia and amblyogenic risk factors in infants. Methods: Since 1968, children bet ween the ages of 1 and 2 1/2 years in the city of Haifa, Israel, have been systematically screened for amblyopia and amblyogenic risk factors. The scr eening is performed by the Ophthalmology Department of Bnai-Zion Medical Ce nter (formerly known as Rothchild Hospital). In 1995, we compared the preva lence and severity of amblyopia in two populations of 8-year-old children i n elementary school: one group was a cohort of 808 children from the city o f Haifa and its vicinity, who had been screened in infancy (between 1988 an d 1990); and the second group, the control group, was a cohort of 782 child ren from Hadera and its vicinity, where this early screening program is not conducted. Amblyopia was defined as corrected visual acuity of less than o r equal to 5/10 (20/40), or >1 line difference in corrected visual acuity b etween the two eyes. Referral rate, treatment rate, sensitivity, specificit y, and positive predictive value and negative predictive value of the scree ning test in detecting factors that later resulted in the development of am blyopia were examined. Results: The prevalence of amblyopia in the 8-year-o ld population screened in infancy was found to be 1.0% compared with 2.6% i n the 8-year-old population that had not been screened in infancy (P = .009 8). The prevalence of amblyopia with Visual acuity of less than or equal to 5/15 (20/60) in the amblyopic eye was 0.1% in the screened population comp ared with 1.7% in the non-screened population (P = .00026). In the screened infant population, 3.6% were referred from the screening examination to a confirmatory examination and 2.2% were treated. The screening examination h ad a sensitivity of 85.7% and a specificity of 98.6% for amblyopia. The pos itive predictive value of the screening examination was 62.1% and the negat ive predictive value was 99.6%. Conclusions: The screening program for ambl yopia and amblyogenic risk factors in infants, followed by appropriate trea tment, is effective in significantly reducing the prevalence and severity o f amblyopia in children.