Abstract
Purpose :
Although Latinos are at higher risk for glaucoma and diabetic retinopathy, lack of health insurance prevents many from seeking routine eye care services. Health fairs may help address this disparity, but the necessary equipment can be prohibitively expensive in low-resource settings. In this study, we evaluated the validity of Visual Fields Easy (VFE), a free iPad-based visual field test by comparing its results to the Humphrey Frequency Doubling Technology (FDT) visual field screening.
Methods :
Latino adults aged 40-80 years were recruited at a health fair in Los Angeles, CA in November 2017. Participants had visual acuity and intraocular pressure measured, followed by FDT testing using the N-30-5 screening protocol, a demographic and health survey, and testing with VFE before being examined by an ophthalmologist. Test time and the number of missed visual field points were recorded for VFE and FDT tests. Pearson’s correlation coefficients were calculated for total points missed, and a Bland-Altman plot was created for the percent of missed points. Correlations were evaluated among all participants and at two age groups (40-60 and 61-80 years old).
Results :
A total of 45 participants (90 eyes) were enrolled, with a mean age of 58.5 years and a standard deviation of 9.5 years. Ninety-three percent of participants were born outside of the United States, with 84% reporting an annual household income of less than $10,000, and only 40% having health insurance. VFE on average took 133.6 seconds longer than FDT (95% Confidence Interval: 130.0-137.2 sec). Pearson’s correlation coefficient (r) was 0.45 for all eyes, increasing to 0.72 for 40-60 year-olds compared to 0.31 for 61-80 year-olds. The Bland-Altman plot showed reduced agreement between VFE and FDT as the number of missed points increased.
Conclusions :
There is good agreement in screening visual field results between VFE and FDT among subjects with minimal visual field loss. VFE might be a promising low-cost screening tool for identifying subjects without visual field defects potentially associated with glaucoma and diabetic retinopathy, especially for high-risk Latino adults attending health fairs. Poor agreement in older adults and subjects with advanced visual field defects suggests that test fatigue and/or usability may be an issue, especially given the longer test time for VFE.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.