Home visual acuity tests yield results similar to in-clinic tests

The use of home visual acuity tests is an important step in expanding ophthalmic telehealth options.

Study design

This was a prospective study involving 121 adult patients recruited from 4 US-based ophthalmology clinics who were asked to self-administer 2 of 3 randomly chosen at-home visual acuity tests (printed chart, mobile phone app, website). Patients performed the tests within 3 days before visiting the clinic, and measurements from the at-home tests and ones performed in the clinic were compared.

Outcomes

At-home testing mildly underestimated visual acuity. The printed chart was the most accurate (difference of <1 line of Snellen acuity). The mobile phone app and website tests showed about 1 line of Snellen acuity worse than what was seen in the clinic, but the differences were not significant. In addition, study participants rated the tests as easy to view and understand, although they did not show strong confidence in the results.

Limitations

Technology was a limiting factor for some participants. This was not a longitudinal study, and it was also conducted only among adults; therefore, it is unknown if these findings are applicable to children, especially those needing different optotypes (e.g., Allen figures or LEA), or if children would be able to complete similar at-home tests.

Clinical significance

During the early part of the COVID-19 pandemic, telehealth visits significantly increased. There is a need for reliable at-home visual acuity testing, as telehealth is more likely to be embraced if there is greater confidence in these tests.