Purpose
This work studied the accuracy and precision of a novel self-service refractor (SSR) that can rapidly assess for myopia, hyperopia, astigmatism and presbyopia by patients themselves, in comparison to autorefraction (AR) and subjective refraction (SR). The refractive errors of the subjects were recorded cycloplegia situation.
Methods
Self-service refractor is a handy monocular device to quantify the refractive error status of the eye, which is mainly composed of lens, test-object board, light source and power source. Refractive error is estimated by subjectively adjusting the lens to the specific position by the subjects themselves. In this study, non-cycloplegia spherical refractive errors of the right eye of 51 adults were measured twice using self-service refractor and averaged. Refractive data of the same eye were also determined using auorefractor (Topcon RM8900) and subjective refraction performed by an experienced optometrist. The refractive errors of the subjects ranged from -0.75D to -8.75D. Exclusion criteria included amblyopia and any ocular pathology.
Results
Fifty-one subjects (51 eyes) underwent AR, SR and SSR refractive assessment, respectively. The age ranged from 17 to 25 years (20.8±1.7 years). The average diopters examined by AR, SR and SSR were -3.22 ± 1.97D, -3.07 ±1.95D and -3.64 ± 2.05D, respectively. There was no statistically significant difference between SSR and AR (p>0.05). The mean absolute difference was 0.72 ± 0.59 diopters. About 80.4% of the subjects had an error smaller than 1.0D between SSR and AR. However, according to the analytical results, there was significantly difference between SSR and SR (p<0.05) with mean absolute difference of 0.79 ± 0.67 diopters. Over 30% of subjects had a refractive error larger than 1.0 D between SSR and SR. Further analysis displayed that two measures, AR and SR, were also statistically significantly different from each other (p<0.05).
Conclusions
This study demonstrated good agreement of SSR with the traditional methods of auto-refraction and subjective refraction in subjects. The results show that SSR has good potential as an effective, simple and portable tool to rapidly estimate refractors errors by non-professionals in a vision-screening program. However, it is necessary to improve further the accuracy of this novel prototype device in estimating refractive errors.
Keywords: 676 refraction •
605 myopia