Baku, June 2 AZERTAC 

British ophthalmologist Andrew Bastawrous moved his family from London to Kenya in 2013 with $150,000 of equipment, a team of 15 people and an ambitious goal: to understand the causes of blindness in rural Africa. It didn't take long before he encountered all sorts of obstacles, including unpredictable power supplies and the regular need to run a gas-fueled generator to keep the equipment going. Many of the villages he was trying to reach had no roads and no electricity.

There had to be a better way, Bastawrous thought as he set about developing a smartphone app to help conduct high-quality eye exams without the need for heavy or expensive equipment. In the first published study on the app, called Peek, he and colleagues report that, for a group of older Kenyans, the phone-based vision test worked just as well as the gold-standard methods used in a doctor's office.

Of the 285 million people in the world with vision impairment, 80 percent live in low-income countries. The vast majority have preventable or treatable conditions, like glaucoma or cataracts. By increasing access to simple and affordable eye tests, Bastawrous hopes to create awareness about eye conditions and, in turn, connect patients with vision-saving treatments.

There are two standard ways to test vision. One is with a traditional letter chart that shows progressively smaller letters as patients read down each line. A newer, more accurate method uses an electronically powered box that illuminates letters of various sizes.

The Peek vision test looks a little different. On the phone's screen, patients see just one letter: an "E" that can be displayed with the prongs facing up, down, to the left or to the right. Patients don't need to be able to read or to know the English alphabet. They just point a finger in the direction they see the E facing. If it looks like a "W," for example, when pointing up.

The test-giver, who does not need to be a trained health care worker, stands 6 feet away and simply swipes the phone to indicate the way the patient thinks the E is positioned. If the patient shakes his head because the letter is too blurry, the test-giver shakes the phone. That's the "don't know" response.

At the end of the test, which takes a little over a minute, the phone vibrates and dings. Results appear immediately on the screen and can be translated to the 20/20 scale. The app can also show the patient's level of blurriness compared to normal vision.

For the latest trial, Bastawrous' team evaluated 233 Kenyans who were 55 or older. At home, patients took two eye exams: one with the Peek app and one with a standard paper chart. The next day, the same people went to a temporary clinic, where they completed the same two tests as well as one with the newer electronic technology.

Results, which appeared Thursday in the journal JAMA Ophthalmology, showed that the Peek test was as accurate as the other two methods for testing vision. The app's test, Bastawrous adds, was as quick if not quicker than the paper chart.