Monthly Archives: January 2016

Smartphone-Based Visual Acuity Measurement for Screening and Clinical Assessment

Christopher J. Brady, MD1; Allen O. Eghrari, MD1; Alain B. Labrique, PhD, MHS, MS2

Commentary discusses a study describes the accuracy of a smartphone-based visual acuity test for detecting visual impairment in rural Kenya.

JAMA Ophthalmology

Development and Validation of a Smartphone-Based Visual Acuity Test (Peek Acuity) for Clinical Practice and Community-Based Fieldwork

Andrew Bastawrous, MRCOphth; Hillary K. Rono, MBBS; Iain A. T. Livingstone, FRCOphth; Helen A. Weiss, PhD; Stewart Jordan, BSc; Hannah Kuper, ScD; Matthew J. Burton, PhD

Importance Visual acuity is the most frequently performed measure of visual function in clinical practice and most people worldwide living with visual impairment are living in low- and middle-income countries.

Objective To design and validate a smartphone-based visual acuity test that is not dependent on familiarity with symbols or letters commonly used in the English language.

Design, Setting, and Participants Validation study conducted from December 11, 2013, to March 4, 2014, comparing results from smartphone-based Peek Acuity to Snellen acuity (clinical normal) charts and the Early Treatment Diabetic Retinopathy Study (ETDRS) logMAR chart (reference standard). This study was nested within the 6-year follow-up of the Nakuru Eye Disease Cohort in central Kenya and included 300 adults aged 55 years and older recruited consecutively.

Main Outcomes and Measures Outcome measures were monocular logMAR visual acuity scores for each test: ETDRS chart logMAR, Snellen acuity, and Peek Acuity. 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 in 2013 and 2014.

Results The 95% CI limits for test-retest variability of smartphone acuity data were ±0.029 logMAR. The mean differences between the smartphone-based test and the ETDRS chart and the smartphone-based test and Snellen acuity data were 0.07 (95% CI, 0.05-0.09) and 0.08 (95% CI, 0.06-0.10) logMAR, respectively, indicating that smartphone-based test acuities agreed well with those of the ETDRS and Snellen charts. The agreement of Peek Acuity and the ETDRS chart was greater than the Snellen chart with the ETDRS chart (95% CI, 0.05-0.10; P = .08). The local Kenyan community health care workers readily accepted the Peek Acuity smartphone test; it required minimal training and took no longer than the Snellen test (77 seconds vs 82 seconds; 95% CI, 71-84 seconds vs 73-91 seconds, respectively; P = .13).

Conclusions and Relevance The study demonstrated that the Peek Acuity smartphone test is capable of accurate and repeatable acuity measurements consistent with published data on the test-retest variability of acuities measured using 5-letter-per-line retroilluminated logMAR charts.

JAMA Ophthalmol. 2015;133(8):930-937. doi:10.1001/jamaophthalmol.2015.1468

Treatment for Intermittent Claudication

From The Journal of Family Practice

Treatment for Intermittent Claudication

Is combination therapy the answer?

December 1, 2015A combination therapy of endovascular revascularization followed by supervised exercise resulted in significantly greater improvement in walking distances and health-related quality-of-life scores compared with supervised exercise only for 212 patients with peripheral artery disease and intermittent claudication who were randomized 1:1 to the interventions. Researchers determined:

• Combination therapy was associated with significantly greater improvement in maximum walking distance (from 264 m to 1501 m for an improvement of 1237 m) compared with the supervised exercise only group (from 285 m to 1240 m for improvement of 955 m).

• The combination therapy group demonstrated significantly greater improvement in the disease-specific VascuQol score compared to the exercise group (1.34 vs 0.73) and in the score for the Short-Form Health Survey (SF-36) physical functioning (22.4 vs 12.6), respectively.

• No significant differences were found in the SF-36 domains of physical role functioning, bodily pain, and general health perceptions.

Citation: Fakhry F, Spronk S, van der Laan L, et al. Endovascular revascularization and supervised exercise for peripheral artery disease and intermittent claudication. JAMA. 2015;314(18):1936-1944. doi: 10.1001/jama.2015.14851.

Commentary:  While it is important to note that surgery plus exercise yielded greater improvement than exercise alone, it is equally important to note the impressive improvement in the exercise alone group. Improving from 285 meters walking to 1240 in the exercise alone group, a greater than fourfold increase in walking distance, is no small task.   In fact, the bulk of the improvement in walking distance occurred with exercise, so it is important to emphasize that if patients opt for surgery, then exercise should still be important as a part of treatment for peripheral vascular disease if optimal outcomes are to be achieved. —Neil Skolnik, MD

Measure
Measure