Evidence of the Amplitude of Accommodation of School-Going Children in the 21st Century

Purpose: The study sought to compare the normative amplitude of accommodation (AoA) in school-going children from studies in the 21st century, based on pooled estimates from meta-analyses, to assess their agreement to Hofstetter’s average formula. Methods: A PRISMA checklist was used to conduct the review. PubMed, EBSCOHOST and Medline electronic databases were employed, and hand searching resulting in 259 studies up to July 2021. After title and abstract screening, 12 studies underwent full-text screening, resulting in five studies for data extraction. The pooled effect size was determined using meta-analyses for sub-groups by age. A one-sample t-test was used to compare the pool-effect size estimates (monocular) to the expected AoA from Hofstetter’s average formula. Results: The comparison of pool estimates of AoA with the expected Hofstetter’s average formula for the age sub-groups showed significant mean differences for: six-year olds: mean difference of –3.4 D (95% CI: –5.85; –1.04; p = 0.025); nine-year olds: mean difference of –4.1D (95% CI: –7.95; –0.20; p = 0.043); ten-year olds: mean difference of –4.6D (95% CI: –8.57; –0.54; p = 0.035) and 11-year olds: mean difference of –5.2 D (95% CI: –8.06; –2.40; p = 0.005). According to the quality assessment tool used, overall, the body of evidence was of good quality. Conclusion: Hofstetter’s prediction of normative amplitude of accommodation today may over-estimate for children aged six, nine, 10 and 11. The observed under-accommodation estimates from these comparisons may warrant consideration in assessing for a larger lag of accommodation in these age groups with myopia or pre-myopia, as part of the surveillance for progression.