Development of a smartphone-based objective eye refractive power assessment method

Abstract

The global prevalence of myopia continues to rise. While objective refraction methods such as autorefractors are available, their high cost and lack of portability limit their application in settings such as developing countries and school-based screenings. In this study, we developed a novel method for refractive error measurement using a smartphone camera, based on the principle of photorefraction. The proposed method was validated through optical simulations and model eye experiments. Moderate correlations were observed between simulation results and model eye data for the width of retroillumination images (r = 0.637, p < .001). Furthermore, analysis of retroillumination images from human eyes enabled estimation of refractive power, which showed a strong correlation with measurements obtained from a conventional autorefractor (r = 0.900, p < .001). These findings suggest that our smartphone-based approach may serve as a low-cost and portable solution for refractive error screening, particularly in resource-limited environments.