Development and Validation of a Smartphone-Based Visual Acuity Test (Vision at Home)

Area of Science:

• Ophthalmology
• Medical Technology
• Digital Health

Background:

• Visual acuity (VA) testing is crucial for eye health assessment.
• Traditional VA testing methods can be resource-intensive and inaccessible.
• Smartphone-based solutions offer potential for wider accessibility.

Purpose of the Study:

• To develop and validate a smartphone-based visual acuity (VA) test named Vision at home (V@home).
• To assess the accuracy and reliability of V@home compared to standard methods.
• To evaluate user satisfaction with the V@home device.

Main Methods:

• V@home and standard Early Treatment Diabetic Retinopathy Study (ETDRS) charts were used for distance and near VA testing with tumbling E optotypes.
• Testing was conducted across three diverse populations: elderly Chinese, adolescent Chinese, and Australians.
• Monocular distance VA was measured at 2m, and binocular near VA at 40cm; test-retest reliability was assessed.

Main Results:

• V@home demonstrated high agreement with ETDRS charts for both distance (mean difference -0.010 to -0.100 logMAR) and near VA (mean difference -0.092 to -0.042 logMAR).
• Tolerant weighted kappa (TWK) values indicated substantial to almost perfect agreement across groups.
• High test-retest reliability was observed for both distance and near VA measurements, with a majority of participants reporting satisfaction.

Conclusions:

• The V@home system accurately and reliably measures both distance and near visual acuity.
• V@home is well-accepted by users and holds potential for enhancing eye care accessibility, particularly in underserved regions.