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Updated: Sep 11, 2025

Subjective Refraction Test Using a Smartphone for Vision Screening
Published on: October 18, 2024
Improving the estimation of the spherical equivalent subjective refraction using objective information on
Aina Turull-Mallofré1, Mikel Aldaba1, Jaume Pujol1
1Centre for Sensors, Instruments and Systems Development, Universitat Politècnica de Catalunya, Rambla de Sant Nebridi 10, Terrassa, 08222, Spain.
Abstract:
Machine learning and deep learning have previously been used to predict the subjective refraction endpoint by objective means with modest success. This study aimed to enhance predictive accuracy by training linear regression models with normal equations using accommodative response and optical quality data. Three models were tested on 176 eyes, with input variables obtained from a Hartmann-Shack aberrometer and an autorefractor. The best model reduced mean absolute error by 40% compared to the objective refraction provided by a commercial autorefractometer and achieved 95% limits of agreement with subjective refraction of ±0.54 D, approaching the subjective refraction inter-examiner variability. Incorporating accommodative response data improved prediction accuracy over objective refraction alone and previous approaches.
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