Distributions of non-cycloplegic subjective refractions at Sekororo Hospital in Limpopo province, South Africa

Abstract

Background: Non-cycloplegic subjective refraction (NCSR) is useful to measure refractive errors with active ocular accommodation. Aim: This study aimed to compare annual NCSR distributions between January 2018 and December 2019. Setting: The study was conducted in the Optometry Clinic at Sekororo Hospital in Limpopo province, South Africa. Methods: Data, extracted retrospectively from the clinical archive, were randomly stratified into two strata (2018 and 2019) for analysis. Stereo-pair scatter plots and polar plots of variance were used to better understand the samples concerned. Results: Clinic patients were mostly females of African descent. Mean ages and standard deviations (± SD) for the 2018 and 2019 samples were similar (48.35 ± 20.86 years and 46.22 ± 20.36 years, respectively). For the 2018 sample, the clinical means for NCSR for the right and left eyes, respectively, were similar (R −0.44 ‒0.15 × 86 and L ‒0.46 ‒0.16 × 75) and similar for the 2019 samples (R ‒0.38 ‒0.17 × 77 and L ‒0.14 ‒0.05 × 99). Samples were not normally distributed and outliers were present, although uncommon. Sample variances were mainly spherical rather than astigmatic. Conclusion: Non-cycloplegic subjective refractions were mostly classified as mild ([−2: 2 D]) compound myopic astigmatism. Severe myopia (|6 D|) and hyperopia were uncommon. Contribution: This article adds to current scientific knowledge of multivariate methods for the analysis of refractive states, especially when applied within rural environments. Such multivariate methods are ideally suited for the analysis of distributions of refractive state.

Keywords

• subjective refractions
• refractive errors
• dioptric power
• refractive distributions
• non-cycloplegic refractions
• distributional non-cycloplegic analysis