Eyeworld

EW INTERNATIONAL 70 August 2015 by Matt Young and Gloria D. Gamat EyeWorld Contributing Writers Peek Acuity follows the standard ETDRS (Early Treatment of Diabetic Retinopathy Study) chart design with a 5 × 5 grid optotype letter E displayed in 1 of 4 orientations (90 degrees, 180 degrees, 270 degrees, and 0 degrees). "The patient points in the direction he sees the legs of the E pointing," Dr. Bastawrous said. "For example, if the backbone of the E is at the bottom and the limbs upward (so it looks like a W), the patient should point up." The examiner then responds to the patient's point- ing with an imitation swipe gesture (i.e., he swipes the screen upward). The examiner does not need to see what is displayed on the screen, Dr. Bastawrous said. "He only needs to respond to the patient's point- ing. As the test progresses, the 'E' orientation randomly changes and gets smaller. If the patient gives the correct or incorrect response, the software will automatically detect this. If the patient shakes his hand or head to indicate he can't see, the examiner shakes the phone to record a 'not seen' response. The test uses a [staircase] algorithm similar to How a U.K.-developed app is changing the landscape of poor vision in rural Africa D espite certain African locations having no roads, electricity, or water, the same places often have a good phone signal, mak- ing them ideal for mobile phone- based visual tests. That's according to Andrew Bastawrous, MRCOphth, oph- thalmologist and clinical lecturer, International Centre for Eye Health, London School of Hygiene & Tropical Medicine, and co-founder of Peek Vision, the co-developer of Peek Acuity. In remote areas such as rural Africa, one of the major causes of blindness is the lack of access to healthcare. A new smartphone app—the Portable Eye Examination Kit (Peek) Acuity—seeks to change that. "While leading the follow-up of a major cohort study of eye disease of 5,000 people in 100 different locations across the Great Rift Valley in Kenya, we found that in the most difficult to reach locations we would find a lot of people who had been unnecessarily blind from prevent- able or treatable diseases. "Together with a brilliant team of developers, engineers, and oph- thalmologists, we developed a suite of smartphone-based tests to see if we could replace some of the stan- dard equipment being used, in the hope that we could make it more portable and easier for non-special- ists to perform, so that ultimately the most high-risk individuals could be reached and treated," Dr. Bastawrous said. One of the tests developed through the collaboration is Peek Acuity. How Peek Acuity works The Peek Acuity test utilizes the smartphone's high-resolution screen and ambient light sensor, which allows healthcare workers or non-healthcare workers (such as teachers) to conduct eye exam- inations even in community-based fieldwork settings. "The examiner opens up the app; on first time use, there are on- screen instructions that include how far to stand from patients, how the patient should cover his eye, and how he should respond to what is on the screen," Dr. Bastawrous said. Smartphone-based visual acuity test important tool in remote areas Vision testing outside patient's home in rural Kenya Source: Peek Vision T he fact that smartphones change the way we interact with each other has never been clearer. Beyond Facebook and instant messaging, we are now using our phone applications to facilitate health- care decisions. Presented here is a simple idea that has the potential to influence how eye exams are done in remote areas. With this application, we now have an easily accessible tool to measure visual acuity that is standardized. It is easy to imagine how this might be useful not only in developing countries but in public screenings, nursing homes, and inpatient exams. When it is made available, this app will be on my smartphone. Read on to see if it has a place on yours. John A. Vukich, MD, international editor what a busy eye doctor might use to quickly calculate a patient's vision without testing every level on the chart." At the end of the test, a vibra- tion alert indicates to the examiner that the test is over and displays the result. This gives the examiner the option to display the result in several notations including Snellen and logMAR and through a vision simulator, SightSim, a useful tool for the caregivers of visually impaired people to understand the visual world of the person just tested. The Peek Acuity test uses the built-in light meter primarily used by smartphones to adjust screen brightness. "While designing and testing this, we monitored the ambient light levels closely and correlat- ed this with the test's accuracy," Dr. Bastawrous said. "We found a definite drop off in accuracy when the brightness hit a certain level, largely due to screen reflections and glare. Now the test includes a built- in warning if those light levels are met." International outlook

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