Refractive error accuracy and user perceptions of a smartphone home-based tester

Abstract

Background: Uncorrected refractive error accounts for nearly half of the global burden of vision impairment. The EyeQue personal vision tracker (EPVT) was created as a convenient smartphone refractometer to be used at home and order spectacles online thereafter. However, its accuracy in diagnosing refractive error has not been fully established.Aim: This study aimed to determine the accuracy of the EPVT in measurement of refractive error and determine user perception on device use.Setting: University of KwaZulu-Natal optometry clinic, Westville campus.Methods: This was a comparative cross-sectional study using a double-blind design. Objective, non-cycloplegic refraction testing results using the EPVT were compared with gold standard ophthalmic subjective refraction (SR). Both eyes were considered for the analysis with comparisons being made between EPVT and gold subjective standard refraction for each eye. User perception was evaluated by means of a structured questionnaire.Results: The mean spherical equivalent refractive error was –0.18 ± 0.70 dioptre (D) and –1.12 ± 2.79 D for the gold standard ophthalmic SR and EPVT, respectively, with significant differences in visual acuities yielded by the two methods (p = 0.000). Participants preferred gold standard refraction testing over the EPVT.Conclusion: The EPVT was not accurate in measuring refractive error; therefore, the resultant prescription from EPVT alone should not be used to order spectacles. However, this digital tool presents promise as an autorefractor for screening refractive error rather than as a diagnostic device.Contribution: This study offered valuable insights into the prospective utility of home-based, self-administered smartphone refractive error testers as a tool for screening of refractive error. The study also provided cautions to the EPVTs limitations related to accuracy and limited ocular health assessment, which have broader implications for visual health and quality.