App Provides Reliable Visual Acuity, Amsler Grid Testing

Senior people lifestyle health problem concept : Portrait photo of senior Asian man has a eye long sighted problem trying to read message from smartphone.
The self-exam can be performed at home and is comparable to in-office tests, the investigation shows.

A mobile-based application can reliably be used to monitor retinal pathology both in the clinic and at patients’ homes, according to research published in American Journal of Ophthalmology.

Telemedicine has proved especially helpful during the COVID-19 pandemic, but a recent study has indicated that visual acuity (VA) remote monitoring tools are limited in accuracy. 

To determine whether the app is suitable for remotely observation of retinal diseases, the researchers conducted an observational study comparing the device’s tests and results to the in-clinic reference tests of Lebensohn Near Vision Card for VA and Amsler Grid paper version for metamorphopsia in the Correlation of Paxos Checkup Mobile App to Standard in Office Vision Assessment (CLEAR) Study ( identifier NCT02871817).

The researchers included 108 adult participants who either had best corrected near visual acuity (BCVA) of at least 20/32 in each eye and otherwise healthy eyes or had age-related macular degeneration (AMD) or diabetic retinopathy (DR) in 1 eye with BCVA of at least 20/200 in each eye. The patients (median age 65 years, 92.6% White) included 63 women and 45 men. 

With each patient, the researchers conducted 2 pairs of exams with the mobile app and reference near-corrected visual acuity assessments as well as 2 app-based Amsler grid assessments and 2 reference Amsler tests at the office visits.

The participants used the app at home for both VA and Amsler grid testing at least 2 times per week and then reported their use of the application at the office visits. At the last visit, they reported their overall experience with the application.

Researchers found strong agreement between the app and the reference tests for visual acuity and Amsler tests (sensitivity 93%, specificity 92%) and excellent agreement between home and clinic testing. Checkup had good reproducibility.

Remote and reference test values both met the upper limit of agreement (LOA) of -0.3 logMAR. While the mobile app test met the upper and lower LOA between the 2 office visits, the reference test only met the lower LOA for agreement between the office visits.

In the patient satisfaction survey, 99% reported they were able to use the app, 94% said they would continue to use it if possible, and 95% said they would recommend it to a friend. They did not report any ocular adverse events related and no patients discontinued the study.

Limitations of the study include possible population selection biases and the necessity of using sponsor-validated devices and operating systems.

Disclosure:  The research was sponsored by Digisight (now Verana Health), which participated in study design; data management, analysis, and interpretation; and preparation, review, and approval of the manuscript. Some study authors declared affiliations with the biotech or pharmaceutical industries. Please see the original reference for a full list of authors’ disclosures.


Khurana RN, Hoang C, Khanani AM, Steklov N, Singerman LJ. A smart mobile application to monitor visual function in diabetic retinopathy and age-related macular degeneration. Am J Ophthalmol. Published online April 5, 2021. doi:10.1016/j.ajo.2021.03.033