Association Between Visual Acuity and Cycloplegic Refractive Error in 3- to <10-Year-Old Children

Distance visual acuity (VA) has been associated with refractive error in older children, but less is known about children <6 years of age and those without a history of refractive correction. This study examined the utility of VA testing and its relationship to refractive error in children aged 3 to <10 years without a history of refractive correction.

Unaided monocular distance VA testing was performed at 3 m (age 3-6 years: ATS-HOTV chart; 7-<10 years: E-ETDRS chart) and near VA at 40 cm (ATS-4 Near VA). Cycloplegic autorefraction was used to categorise participants as myopic (sphere ≤ -0.75 dioptres (D)), hyperopic (sphere ≥2 D), astigmatic (cylinder ≥1.50 D) and emmetropic (< 0.75 D myopia and <2 D hyperopia). Receiver operating characteristic curves assessed the utility of VA testing in classifying children by refractive error type. Linear regressions examined the predictive value of refractive error magnitude in determining distance and near VA while accounting for age.

Of 358 children, 84 (23.5%) had hyperopia, 30 (8.4%) myopia, 39 (10.9%) astigmatism and 229 (64.0%) emmetropia. Reduced distance VA was associated with myopia (area under the curve (AUC) = 91%, optimal cut-off = 0.15 logMAR) and astigmatism (AUC = 87%, cut-off = 0.25 logMAR), but not hyperopia (AUC = 63%, cut-off = 0.05 logMAR). Near VA showed only mildly higher performance for hyperopia (AUC = 70%, cut-off = 0.15 logMAR). For every 0.36 D increase in myopia, distance VA declined by 0.10 logMAR (p < 0.001). Distance and near VA were not predicted by the magnitude of hyperopia (distance: p = 0.30; near: p = 0.30) or astigmatism (distance: p = 0.35; near: p = 0.06).

In children 3 to <10 years of age without prior refractive correction, reduced distance VA was associated with myopia and astigmatism, but not hyperopia; an incremental decline in VA with increasing refractive error magnitude was seen only in myopia.