# Combining visual acuity with refraction reduces overestimation of myopia prevalence in school screenings: an age-stratified analysis

## TL;DR

Adding visual acuity to refraction tests in school myopia screenings reduces overestimation, especially in younger children.

## Contribution

The study introduces an age-stratified SER + UCVA criterion that improves accuracy in identifying visually significant myopia.

## Key findings

- The SER + UCVA criterion reduced myopia prevalence estimates by 15–21% compared to SER-only.
- Overestimation was most severe in children aged 5–6 years, with prevalence nearly double.
- From age 10 onwards, myopia prevalence was significantly higher in females than males.

## Abstract

School myopia screening commonly employs non-cycloplegic spherical equivalent refraction (SER ≤ −0. 50 D) for its practicality. However, this SER-only approach likely overestimates the prevalence of visually significant myopia, as it cannot distinguish true myopia from accommodative pseudomyopia, especially in younger children. We quantified the disparity between this SER-only criterion and a combined criterion integrating uncorrected visual acuity (UCVA), the SER + UCVA criterion, and examined its variation across age groups.

This serial cross-sectional study (2018–2021) included 20,750 students aged 5–18 years from Southern China. Myopia was defined using two criteria based on non-cycloplegic measurements in at least one eye: (1) SER-only: SER ≤ −0.50 D; and (2) SER + UCVA: SER ≤ −0.50 D plus age-impaired UCVA (>0.20 logMAR at age 5; >0.00 logMAR at ages ≥6) in the same eye. Age-stratified prevalence estimates were compared.

The SER + UCVA criterion yielded consistently lower prevalence estimates than the SER-only criterion (e.g., 48.89% vs. 59.48% in 2021), corresponding to a 15–21% annual relative overestimation. Crucially, this overestimation demonstrated a strong age gradient. It was most severe in young children, with the SER-only myopia prevalence nearly double the SER + UCVA myopia prevalence at ages 5–6 years (relative difference >50%), and progressively narrowed to approximately 10–15% in adolescents (14–18 years). Notably, a significant acceleration in SER + UCVA myopia prevalence was observed in children aged 7–10 years between 2019 and 2020. Furthermore, from age 10 onwards, SER + UCVA myopia prevalence was significantly higher in females than males (all P < 0.001).

Sole reliance on non-cycloplegic SER substantially overestimates the burden of visually significant myopia, especially in younger children. Incorporating UCVA provides a more accurate and functionally relevant metric for public health screening. We advocate for adopting age-specific SER + UCVA criteria in school-based screenings to optimize referral efficiency, with the greatest benefit expected for younger populations where specificity gains are maximal.