Eyeworld

71 EW INTERNATIONAL August 2015 perform "test-retest," Dr. Bastawrous said. "We found that for both Peek Acuity and Snellen, they were highly repeatable. An advantage of Snellen is the speed of the test; Peek Acuity came out slightly quicker overall. We also found, when compared to the reference standard test, Peek Acuity was highly comparable and within a clinically acceptable limit of difference." What's next for Peek Acuity? Currently, Peek Acuity is being used for research trials only. The app will be freely available from the Google Play store once it has completed certification as a medical device and will likely follow on iOS and the Apple Store soon after. Dr. Bastawrous and his team have recently completed a pilot study where teachers used Peek Acuity to screen school children for visual impairment. Twenty-five teachers were able to screen almost 21,000 children in 2 weeks. As with any new tool, there are limitations. The developers of Peek Acuity have addressed as many of the limitations as possible, Dr. Bastawrous said. "As the test is designed to be portable, it does mean we cannot guarantee the ideal testing environ- ment that is likely to be in place for reference standard tests," Dr. Bastawrous said. For example, a warning on am- bient light is in place together with built-in instructions to minimize such limitations. In addition, the Peek Acuity app was only tested on a handful of smartphone handsets. "Theoretically this shouldn't cause any problems, but in practice we expect surprises and bugs that we need to fix," Dr. Bastawrous said. "This will all be part of the ongoing improvement for Peek Acuity." Future research on Peek Acuity should include using the test in different populations across different handsets in real world scenarios. EW Editors' note: Dr. Bastawrous is co-founder of Peek Vision. Contact information Bastawrous: andrew.bastawrous@lshtm.ac.uk Results of Peek Acuity validation study In a paper published in May in JAMA Ophthalmology, Dr. Bastawrous and colleagues reported the findings of the development and validation study of Peek Acuity for clinical practice and community-based fieldwork. "The study demonstrated that the Peek Acuity smartphone test is capable of accurate and repeatable acuity measurements consistent with published data on the test-re- test variability of acuities measured using 5-letter-per-line retroilluminat- ed logMAR charts," they wrote. Written on an Android plat- form, the Peek Acuity app was used on a Galaxy S III GT-I9300 running Android 4.0 during the validation study conducted from December 11, 2013, to March 4, 2014. To validate its measurement accuracy, Peek Acuity was compared (in terms of test-retest variability and measurement time) with the Snellen acuity and ETDRS logMAR charts in participants' homes and temporary clinic settings in rural Kenya during the study period in 2013 and 2014. Despite the positive results of the validation study, Dr. Bastawrous emphasized that only time will tell how Peek Acuity is adopted by the ophthalmic community. "We've tried to remove as many barriers as possible; the test is accu- rate, repeatable, fast, free, indepen- dent of language, and the results can be shared in familiar and intuitive ways," he said. While Peek Acuity was primarily designed for use by non-clinicians, its developers hope that the rigor with which it has been designed will lead to its extensive use. "Our field workers tested patients in their own homes us- ing a standard card-based Snellen chart [the type of vision test most non-ophthalmic healthcare workers are familiar with] and Peek Acuity," Dr. Bastawrous said. The same tests were repeated by the same healthcare worker in the clinic the following day as well as a reference standard vision test (logMAR ETDRS) performed by an eye-trained clinical officer. This allowed the research team to

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