eHealth tools for the self-testing of visual acuity: a scoping review

Area of Science:

• Ophthalmology
• Public Health
• Digital Health

Background:

• Uncorrected refractive error is a leading cause of vision impairment globally.
• Access to vision assessment is restricted in low/middle-income countries and minority populations.
• Mobile devices offer a scalable platform for eHealth solutions in vision care.

Purpose of the Study:

• To conduct a scoping review of available mobile applications for self-testing visual acuity.
• To assess the quality and features of these eHealth tools.
• To identify gaps in validation and potential risks associated with self-testing tools.

Main Methods:

• Searched Google, Google Play, and iOS stores for visual acuity self-testing applications.
• Screened the first 100 results from each search against predefined inclusion criteria.
• Reviewed 42 selected applications for features like optotype presentation and calibration.
• Excluded software intended for professional clinical use.

Main Results:

• 42 mobile applications for self-testing visual acuity were identified and reviewed.
• Approximately half (n=20) utilized custom optotypes, and most (n=25) displayed optotypes individually.
• Only four applications included a calibration procedure.
• Critically, only one tool was validated against established gold-standard measures.

Conclusions:

• Numerous mobile tools for self-testing visual acuity exist, but most lack scientific validation.
• The absence of validation poses risks of confusion and potential harm to users.
• There is a pressing need for regulatory oversight and standardization of visual acuity self-testing applications.