Refractive amblyopia in a native american preschool population with a high prevalence of astigmatism

Purpose. To determine the pre valence of refractive amblyopia in a population of preschoolers with a high prevalence of astigmatism. Methods. Seventy-seven Tohono O'Odham children (31/2 to 5 years old) participated. Right eye LEA distance acuity was measured before cycloplegic autorefraction (Nikon letinomax K-Plus, Melville, NY). The LEA distance acuity was then rete ited in best correction. Results. Red reflex testing detec ed one dense cataract. This child was dropped from further analysis. No significant strabismus was identified. Prior to dilation, LEA acuity was obtained on 70 of 76, and 15 of 70 (22%) had acuity of 20/80 or worse. Autorefraction was obtained on all 76 children. Astigmatism >2D was present in the right eye in 20 of 76 (26%). After dilation, in best correction, acuity was obtained on 64 of 76, and 8 of 64 (12.5%) had acuity of 20/80 or worse. Best corrected vision was inversely correlated with amount of astigma ism (Rs - 0.39, p = 0.001). Conclusion. Astigmatism is the overwhelming risk factor for amblyopia in this population, and screening efforts should reflect this fact.