Does refractive error type affect amblyopia recovery? Evidence from a sample of Moroccan children.

Abstract

Purpose: To determine whether the type of refractive error influences visual acuity recovery in children with anisometropic amblyopia and to assess differences in treatment responsiveness across hyperopic, myopic, and astigmatic anisometropia. Methods: A prospective longitudinal interventional study was conducted on 54 children aged 3-9 years diagnosed with unilateral anisometropic amblyopia. Participants were classified into three groups based on refractive error: hyperopic anisometropic amblyopia (HAA, n = 17), myopic anisometropic amblyopia (MAA, n = 18), and astigmatic anisometropic amblyopia (AAA, n = 19). All children underwent refractive adaptation followed by a standardized occlusion schedule according to amblyopia severity. Visual acuity was assessed using logMAR charts at baseline and at Weeks 4, 8, 12, and 16. One-way ANOVA was used to compare visual outcomes between groups overall and within severity subgroups (mild, moderate, severe). Results: All groups showed significant improvement in amblyopic-eye visual acuity over the 16-week period; however, the magnitude of recovery differed according to refractive error type. As early as Week 4, children with myopic anisometropic amblyopia showed significantly greater visual improvement compared with the hyperopic and astigmatic groups, with differences becoming highly significant by Week 8. Highly significant differences were observed across all severity levels (all p < .001). At Week 16, final mean visual acuity reached 0.30 ± 0.05 (HAA), 0.06 ± 0.04 (MAA), and 0.13 ± 0.09 logMAR (AAA), with strong statistical significance between groups (p < .0001). The MAA group showed the greatest overall improvement, followed by AAA and HAA. Conclusion: Refractive error type significantly influences visual outcomes in children with anisometropic amblyopia after 16 weeks of occlusion therapy. Myopic anisometropia is associated with better final visual acuity at the 16-week follow-up, whereas hyperopic anisometropia demonstrates comparatively poorer visual outcomes. These results suggest that refractive error type should be considered a key prognostic factor when individualizing amblyopia management strategie.