Smartphone-based Snellen charts are not as reliable as standard chart tests, according to a study conducted by researchers from the University of Melbourne. The results of the study were published in Eye, which is the official journal of The Royal College of Ophthalmologists.

The Snellen test involves a patient reading numbers and letters line by line from a physical chart while standing a specific distance away. The numbers and letters decrease in font size the lower the patient reads.

“Smartphone-based Snellen visual acuity charts [have] become popularized; however, their accuracy has not been established,” researchers wrote in the abstract. “This study aimed to evaluate the equivalence of a smartphone-based visual acuity chart with a standard 6-m Snellen visual acuity (6SVA) chart.”

Researchers were reviewing 11 iPhone apps, and have found that their accuracy varied significantly, from 4 to 40 percent. They then conducted a study with 88 patients from general medical and surgical wards in an Australian hospital to compare results from a conventional test and the most accurate app from the review. The iPhone 4 was used for the test.

The comparison showed that the Snellen visual acuity app could not predict a patient’s standard Snellen visual acuity within one line. Researchers, however, added that further validation is required to assess the acuity in patients with severe vision impairment.

No Snellen test app got an FDA clearance, but there’s at least one vision test application that got the certification from the FDA. That would be Vital Art and Science’s myVisionTrack, which is a vision test for patients with age-related macular degeneration or diabetic eye disease. This app received a second FDA clearance for the platform, which includes an app and a provider dashboard.

[Via: mobihealthnews]