Refractive error correction among urban and rural school children using two self-adjustable spectacles

Abstract

ObjectiveSelf-refracting spectacles (SRSs) have different optical and mechanical designs, which may affect the refractive outcome, depending on the experience of the end user. This study compared the performance of two SRS among children in Ghana.Methods and analysisA cross-sectional study of two Alvarez variable-focus SRS designs was conducted. A total of 167 children (mean age 13.6±1.6 years) identified as having refractive error were recruited from 2465 students who underwent screening. Subjects completed self-refraction using FocusSpecs, and Adlens, autorefraction and cycloplegic subjective refraction (CSR) (gold standard). Wilcoxon signed-rank test was used to compare visual outcomes and accuracy of refraction and graphically illustrated using Bland-Altman plots.ResultsEighty (47.9%) urban and 87 (52.1%) rural children were analysed and only about one-quarter 40 (24.0%) wore spectacles. The proportion who achieved visual acuity of ≥6/7.5 with FocusSpec, Adlens, autorefraction and CSR among urban schools were 92.6%, 92.4%, 60% and 92.6%, while those in rural schools were 81.6%, 86.2%, 54.0% and 95.4%, respectively. The mean±SD spherical equivalent errors for urban and rural schools using FocusSpec, Adlens and CSR were −1.05±0.61 D, –0.97±0.58 D and −0.78±0.53 D; and −0.47±0.51 D, –0.55±0.43 D and −0.27±0.11 D, respectively. The mean differences between the two self-refraction spectacles for urban and rural schools were not statistically different (p>0.00) but differed significantly when both were compared with the gold standard (CSR) (p<0.05).ConclusionBackground and refraction experience of school children did not significantly affect self-refraction.

Refractive Accuracy and Visual Outcome by Self-Refraction Using Adjustable-Focus Spectacles in Young Children

“…Compared with noncycloplegic autorefraction, we found self-refraction using fluid-filled design adjustable-focus spectacles to be noninferior and more hyperopic (mean difference, 0.32 D) among children aged 5 to 11 years. In contrast, a study among older children (12-17 years) in rural and urban Ghana using Alvarez design adjustable-focus spectacles found a significant myopic difference between self-refraction and noncycloplegic autorefraction (mean difference, −0.24 to −0.26 D) . We did not find a definitive association between the mean difference in refractive power between self-refraction and noncycloplegic autorefraction and either age or refractive power of cycloplegic refraction.…”

“…Consistent with previous self-refraction studies, we found a tendency toward greater myopic power, although no definitive difference, with self-refraction compared with cycloplegic refraction among children aged 5 to 11 years, likely due to noncycloplegic accommodation . The mean dioptric power inaccuracy reported in prior studies with older children (12-17 years) was −0.22 to −0.44 D, similar to what we observed among 5 to 11 year olds (−0.33 D) . We did not find a definitive association between difference in refractive power between self-refraction and cycloplegic refraction and age (ie, no increased tendency to overminus with younger age).…”

“…In contrast, a study among older children (12-17 years) in rural and urban Ghana using Alvarez design adjustable-focus spectacles found a significant myopic difference between self-refraction and noncycloplegic autorefraction (mean difference, −0.24 to −0.26 D). 10 We did not find a definitive association between the mean difference in refractive power between self-refraction and noncycloplegic autorefraction and either age or refractive power of cycloplegic refraction. Consistent with previous self-refraction studies, we found a tendency toward greater myopic power, although no definitive difference, with self-refraction compared with cycloplegic refraction among children aged 5 to 11 years, likely due to noncycloplegic accommodation.…”

“…In prior studies using fluid-filled design adjustable-focus spectacles in rural and urban China, children aged 12 to 18 years achieved corrected VA of 20/25 or better in better-seeing eyes by self-refraction in 92% to 97% of cases . In prior studies using Alvarez design adjustable-focus spectacles in rural and urban Ghana, children aged 12 to 17 years achieved corrected VA of 20/25 or better in 81.6% to 92.6% of better-seeing/right eyes . In the current study using fluid-filled design adjustable-focus spectacles in a younger population of children (5-11 years), we found corrected VA of 20/25 or better in 79.5% of study eyes and 20/32 or better in 93.8% of study eyes.…”

“…A variety of different devices for self-refraction use 2 main optical designs: (1) the Alvarez design that involves 2 lenses being slid across one another to alter the lens power (eg, Adlens [Eyejusters 2015] and FocusSpecs [Focus-on-Vision]) and (2) a fluid-filled design (eg, Adspecs [Adaptive Eyecare]) adjustable-focus spectacles. Although the refractive and visual outcomes of self-refraction with adjustable-focus spectacles are comparable with noncycloplegic autorefraction and cycloplegic refraction in children 12 years and older, their use has not been evaluated in children younger than 12 years.…”