Refractive factors affecting the persistence of anisometropia in preschool-aged children.

Purpose: Pediatric vision screening programs can detect children with amblyopic anisometropia. We aim to determine which refractive factors may be associated with the persistence of anisometropia in this population.

Methods: A cohort analysis included all children aged one to six years, evaluated for refractive status between 2012 and 2022 at the Maccabi Healthcare Services. Refractive data were collected at presentation and at a subsequent follow-up visit. Logistic regression models were used to analyze relationships between baseline refractive error and anisometropia at follow-up.

Results: Of 35,854 children evaluated, 6.6% (n = 2,358) had anisometropia at presentation. Those with a baseline anisometropia of ≥ 3.0 diopters exhibited a higher prevalence of anisometropia at the last follow-up compared to those with a baseline anisometropia of a lesser magnitude; when the more ametropic eye was hyperopic (73.5% vs. 41.4%, respectively, p < 0.001) or myopic (62.5% vs. 41.8%, respectively, p = 0.009). Adjusted odds ratios for anisometropia at follow-up increased with greater levels of baseline anisometropia with the more ametropic eye being hyperopic (OR = 3.75, 95% CI 2.57 - 5.48) or myopic (OR = 2.19, 95% CI 1.11 - 4.33). A higher degree of hyperopia, myopia and astigmatism at baseline demonstrated similar patterns.

Conclusion: In anisometropic preschool-aged children, higher degrees of baseline anisometropia, hyperopia, myopia and astigmatism, are associated with a higher prevalence of future anisometropia. The likelihood for later anisometropia increases with greater levels of baseline anisometropia, hyperopia, myopia and astigmatism.

Key messages: What is known Higher refractive errors, lifestyle factors and educational levels have been considered as risk factors for anisometropia. Severe anisometropia at young age is more prone to persist. What is new In this cohort of 2,358 anisometropic preschool-aged children, the likelihood for anisometropia at the last follow-up has increased considerably when, at baseline, the more ametropic eye was hyperopic. It has also increased with astigmatic hyperopia, which possibly underscores the combined effect of astigmatism and hyperopia on anisometropia persistence. These findings were independent of socio-economic status, body mass index, and country of birth.