Use of Visual Acuity to Screen for Significant Refractive Errors in Adolescents

Abstract

To detect significant refractive error in a population-based random cluster sample of 12-year-old schoolchildren by using sensitivity and specificity of uncorrected visual acuity (VA). Methods: The Sydney Myopia Study randomly selected 21 secondary schools stratified by socioeconomic status. All year 7 students (mean age, 12.7 years) were invited to participate. We tested VA monocularly, unaided at 2.44 m, using a retroilluminated logMAR chart. Cycloplegic autorefraction (induced with instillation of cyclopentolate hydrochloride, 1%) was used to define clinically significant refractive error as a spherical equivalent of −1.00 diopters (D) or less for myopia; at least ϩ2.00 D for hyperopia; and −1.00 D or less cylinder power for astigmatism. Results: Data for both eyes were pooled for a total of 4497 observations. The sensitivity and specificity for all clinically significant refractive errors at the best VA cutoff level of 53 letters (6/6 −2) were 72.2% and 93.3%, respectively. Myopia had the highest sensitivity and specificity of any of the refractive errors for detection using VA (97.8% and 97.1%, respectively, for a 45-letter VA cutoff [6/9.5]). The best VA cutoffs for hyperopia and astigmatism were 57 (6/ 6 ϩ2) and 55 (6/6) letters, respectively, with sensitivities of 69.2% and 77.4%, respectively, and specificities of 58.1% and 75.4%, respectively. Conclusions: In this adolescent group, a VA cutoff of 6/9.5 or less detects myopic refractive error reliably. However, there is no reliable VA cutoff for clinically significant hyperopia or astigmatism. Improved VA screening methods are required to improve detection of these conditions. Even so, with the methods described herein, the prevalence of uncorrected VA may provide a reasonably accurate estimate of the prevalence of myopia.

Increases in the prevalence of reduced visual acuity and myopia in Chinese children in Guangzhou over the past 20 years

“…14 Analysis of the factors involved is complicated by the fact that the epidemic of myopia has already occurred, without the collection of longitudinal data on cycloplegic refractions and risk factors. Recent analyses 15,16 have confirmed earlier suggestions 17 that low unaided VA in children provides a proxy measure of myopia. The evidence for longitudinal change in Singapore is primarily based on VA measurements, [18][19][20] but the high prevalence of myopia has been confirmed with non-cycloplegic autorefraction.…”

“…Similar patterns of secular change were observed for both boys and girls, although girls showed consistently slightly more moderately and severely reduced unaided VA, consistent with the higher prevalence of myopia in girls. 2 On the basis on the high correlation between the VA measurements from Guangzhou and the prevalence of myopia from the Guangzhou RESC study, 2 and the validation of reduced VA as a predictor for myopia in the Singapore SCORM and Sydney Myopia studies, 15,16 we suggest that the changes in VA over this 20-year Eye period are largely due to an increasing prevalence of myopia. The characteristics of earlier onset, greater severity at the end of school, and current stabilization have previously been described in Taiwan for myopia.…”

Traffic-related air pollution and spectacles use in schoolchildren

“…We considered use of spectacles as a surrogate for refractive errors of vision and specifically myopia because when low visual acuity increases during childhood, this is particularly likely to be associated with the onset of myopia [15–17]. Our choice of primary schoolchildren to test our hypothesized association was in line with most studies (e.g.…”

Uncorrected Distance Visual Impairment Among Adolescents in the United States

“…Further details regarding the vision examination are available elsewhere [4]. We used 20/40 or worse in the better-seeing eye, with correction if available, as the threshold for distance VI because it has high accuracy for classifying myopia (sensitivity and specificity Ͼ 97%) [5]. Unfortunately, there is no threshold to adequately classify hyperopia or astigmatism.…”