Peek eye test app works as well as visual acuity charts

28 May 15

written by:

Ade Deane-Pratt

(more articles)

Study shows the Peek Acuity app is as fast and accurate as using standard eye charts.

Tumbling E screenshot Peek Acuity © Peek.
Tumbling E screenshot of Peek Acuity © Peek


An app to test eyesight easily and affordably using a smartphone is as fast and accurate as traditional charts, according to a study published today.

Peek (the Portable Eye Examination Kit) is a unique smartphone-based system for comprehensive eye testing anywhere in the world. It has been designed and developed, with part-funding from Fight for Sight, by the London School of Hygiene & Tropical Medicine, the University of Strathclyde and the NHS Glasgow Centre for Ophthalmic Research.

Globally, 285 million people are visually impaired and 80% have conditions could be cured or prevented. However, most live in low-income countries and have limited access to specialist clinics. Peek offers a solution by enabling health workers to test eyes easily and affordably in the community.

Peek consists of a series of apps and a unique piece of hardware called Peek Retina. This study focused on one of the apps, called Peek Acuity, which determines how clearly an individual sees.

Touch screen captures gestures

Peek Acuity is designed not to rely on people being familiar with the letters and symbols in written English. It features a “tumbling E” on screen, showing the letter E facing in 1 of 4 directions. Patients point in the direction they think the arms of the E are facing. The tester then swipes the touch screen to translate the gesture from the patient to the phone.


Dr Bastawrous with Peek healthcare worker, Cosmas.
Dr Andrew Bastawrous (left) with Cosmas, a Peek healthcare worker

The study was led by Dr Andrew Bastawrous, Lecturer in International Eye Health at the London School of Hygiene & Tropical Medicine and co-founder of Peek. He said:

“With most of the world’s blind people living in low-income countries, it is vital we develop new tools to increase early detection and appropriate referral for treatment. Mobile phone use is now so widespread that it seemed to be an ideal platform.

“In this study we aimed to develop and validate a smartphone-based visual acuity test for eyesight which would work in challenging circumstances, such as rural Africa, but also provide reliable enough results to use in routine clinical practice in well-established healthcare systems.

The chance to see clearly again

“Our ultimate hope is that the accuracy and easy to use features of Peek will lead to more people receiving timely and appropriate treatment and having the chance to see clearly again.”

The research, published in JAMA Ophthalmology, involved testing 233 people in their own homes and was repeated in eye clinics based in Kenya. The team is also conducting other studies to find out how well the tool works with different handsets and operating systems, including a trial involving teachers testing over 20,000 schoolchildren.