In Preschoolers, Higher Baseline Anisometropia, Ametropia Linked to Increased Prevalence

This study’s findings possibly underscore the combined effect of astigmatism and hyperopia on anisometropia persistence. Earlier development of unilateral defocus in the presence of astigmatism, and astigmatic hyperopia in particular, may disrupt emmetropization to a greater extent than other types of refractive errors. Photo: Matt Ward, MD/eyerounds.org. Click image to enlarge. Severe anisometropia at a young age is more prone to persist. Although older children may present with a large anisometropic refractive error, it was probably present at preschool age, experts say. Given the lifelong impact the condition can have, researchers have an interest in better understanding what causes it to arise. High refractive error has long been considered a key risk factor for anisometropia. Researchers recently conducted a study on a large sample of anisometropic young children covering a broad range of refractive errors to determine which refractive factors may be associated with the persistence of anisometropia in this population. They determined that the likelihood for anisometropia at the last follow-up had increased considerably when, at baseline, the more ametropic eye was hyperopic. It had also increased with astigmatic hyperopia, which possibly underscores the combined effect of astigmatism and hyperopia on anisometropia persistence.The study worked with a cohort of 2,358 anisometropic preschool-aged children (51.7% boys). The mean age at the first examination was 3.7 years. The mean follow-up period was 5.1 years.Those with a baseline anisometropia of ≥3D 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) or myopic (62.5% vs. 41.8%, respectively). Adjusted odds ratios for anisometropia at follow-up increased with greater levels of baseline anisometropia, with the more ametropic eye being hyperopic (odds ratio; OR = 3.75) or myopic (OR = 2.19). A higher degree of hyperopia, myopia and astigmatism at baseline demonstrated similar patterns.“Our study again emphasizes the importance of preschool refraction screening, in order to determine who are the children at risk of continuing anisometropia based on baseline refractive measurements,” the researchers wrote in their paper, which was published in Graefe's Archive for Clinical and Experimental Ophthalmology. “Prescribing refractive correction by itself is an inherent intervention in this study that may impact the amount of persistent anisometropia at the follow-up visit, which would have otherwise might have been even higher.”The team did note that potential limitations include the context of the first refractive examination not being accounted for, as to whether it was part of a routine screening examination or following a medical referral regarding a specific ophthalmic pathology, which may cause bias. Also, their cohort was too young to demonstrate relationships with myopia to the fullest, which can become evident only at a later age.They concluded that further research should focus on how to practically implement these findings in clinical practice in order to target patients who are at increased risk of anisometropia persistence and place them on a closer follow-up or earlier treatment.Click here for the journal source. Moshkovsky R, Nitzan I, Kinori M, Spierer O. Refractive factors affecting the persistence of anisometropia in preschool-aged children. Graefes Arch Clin Exp Ophthalmol. June 27, 2025. [Epub ahead of print].