The Agreement Between an iPad Visual Field App and Humphrey Frequency Doubling Technology in Visual Field Screening at Health Fairs.

Abstract

This is the first exploratory study demonstrating the promising potential of app-based visual fields testing in a low-resource health fair setting for community screening of high-risk Latino adults. To compare the "Visual Fields Easy" (VFE) iPad application against the Humphrey Frequency Doubling Technology (FDT) N-30-5 in detecting abnormal visual fields in a low-resource health fair setting. Latinos aged 40 to 80 years were recruited at a health fair in Los Angeles, California, in November 2017. Both eyes were tested using VFE and FDT. To account for possible nested correlations between participants and eyes, linear mixed effects models were used to estimate the difference in test time and the association in percent of missed points. A Bland-Altman plot and receiver operator characteristic curve were constructed for further comparisons. Forty-five participants with a mean age of 58.5 years (SD=9.5 y) were recruited and both eyes were tested (90 eyes). VFE testing took on average 141 seconds longer per eye than FDT (95% confidence interval: 137-145 s), and FDT resulted in having 7.50% more missed points than VFE (95% confidence interval: 2.56%-12.43%, P=0.002). The Bland-Altman plot depicted reduced agreement with increasing average of percent of points missed. The sensitivity and specificity of VFE were 67% and 77%, respectively, with an area under the receiver operator characteristic curve of 0.71. In this exploratory study, VFE exhibited moderate discrimination for identifying Latino adults with abnormal visual fields compared with FDT. Agreement between FDT and VFE was greater for patients with mild-to-moderate visual field loss. Further software enhancements of app-based fields testing, in concert with other portable testing, represents promising screening methods for high-risk groups in resource-limited environments.