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Subjective Refraction Test Using a Smartphone for Vision Screening
Published on: October 18, 2024
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Real-world application of a smartphone-based visual acuity test (WHOeyes) with automatic distance calibration
Yi Wu1, Stuart Keel2, Vera Lúcia Alves Carneiro2
1State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, China.
The British Journal of Ophthalmology
|March 21, 2024
Summary
The WHOeyes smartphone app accurately measures visual acuity (VA) and testing distance, matching the gold standard ETDRS chart. Its automatic distance calibration ensures reliable results across age groups, offering an excellent user experience.
Area of Science:
- Ophthalmology
- Medical Technology
- Digital Health
Background:
- Smartphone-based visual acuity (VA) testing offers a portable alternative to traditional methods.
- The WHOeyes app was developed to enhance VA testing with an automatic distance calibration (ADC) function.
Purpose of the Study:
- To develop and assess the usability of the iOS version of WHOeyes, a smartphone-based VA test with ADC.
- To evaluate the accuracy and reliability of WHOeyes compared to a standard VA testing method.
Main Methods:
- WHOeyes, an upgraded VA app with ADC, was tested on three age groups of Chinese participants.
- Distance and near VA were assessed using WHOeyes and the Early Treatment Diabetic Retinopathy Study (ETDRS) chart.
- Infrared rangefinder confirmed testing distances; user satisfaction was evaluated via questionnaire.
Main Results:
- WHOeyes ADC demonstrated good agreement with desired testing distances across all age groups.
- The accuracy of WHOeyes VA testing was equivalent to the ETDRS chart (mean difference -0.084 to 0.012 logMAR, QWK >0.75).
- High test-retest reliability was observed for both near and distance VA (QWK >0.85), with excellent user experience reported.
Conclusions:
- WHOeyes provides accurate measurement of testing distance and visual acuity, comparable to the ETDRS chart.
- The app's ADC function ensures reliable distance calibration for VA testing.
- WHOeyes demonstrates high accuracy, reliability, and user acceptance for smartphone-based vision assessment.
