Ethnic variation in strabismus patterns in Down syndrome
Reviewed by Hannah Thomsett

The authors present a systematic review and meta-analysis evaluating the prevalence and aetiology of strabismus in individuals with Down syndrome, with particular focus on ethnic variation in the esotropia to exotropia ratio. Data from multiple studies across diverse populations were synthesised, confirming that strabismus is highly prevalent in this group. Esotropia was the predominant deviation overall, although the relative distribution of esotropia and exotropia varied significantly between ethnicities. In Caucasian populations, where esotropia is already more common, this effect was pronounced, resulting in a markedly higher esotropia to exotropia ratio. In contrast, in populations where exotropia is more prevalent, such as West African, Asian and Hispanic groups, the shift towards esotropia was less marked, leading to a comparatively lower ratio. This suggests that while Down syndrome exerts a consistent influence towards esotropia, underlying ethnic patterns continue to modulate the overall strabismus phenotype. Strengths of this study include its systematic approach and large pooled sample size, enabling meaningful cross-population comparisons. However, heterogeneity in study design, diagnostic criteria and age ranges may limit direct comparability. Potential publication bias and variable study quality are additional limitations. Despite this, the findings provide important insight into the interaction between genetic and population factors in strabismus, with implications for targeted screening and management in children with Down syndrome.

Prevalence and aetiology of strabismus in Down syndrome: A systematic review and meta-analysis with a focus on ethnic differences in the esotropia/exotropia ratio.
von Bartheld CS, Chand A, Wang L.
OPHTHALMIC EPIDEMIOLOGY
2025;32:633–51.