Low-cost, smartphone based frequency doubling technology visual field testing using virtual reality

Abstract

Purpose : Glaucoma is a progressive disease that eventually leads to vision loss. Frequency doubling technology (FDT) based perimetry is a relatively inexpensive and portable visual field test with a short testing time that has shown reasonable efficacy, sensitivity, and specificity in screening for glaucoma in clinic and community-based settings. Current visual field screening machines are bulky and expensive, limiting their accessibility, affordability, and use. The aim of our study was to develop a portable, low-cost smartphone-based FDT perimeter for visual field screening.

Methods : Twenty-nine eyes of fifteen subjects (average age 61 ± 14) with new-onset or chronic primary open angle glaucoma were tested and compared with the Humphrey Zeiss FDT and the newly developed smartphone FDT using the C-20 testing pattern. Mann-Whitney, Bland-Altman, and linear regression analyses were performed to assess statistical difference, agreement, and correlation, respectively, between the two devices by comparing the total number of defects identified in each quadrant.

Results : No statistically significant difference was found between the two FDT exams in all sections (Mann-Whitney test, p > 0.05). The Bland-Altman scatterplot indicated good agreement and the linear regression resulted in a high correlation coefficient (R2 = 0.72). The average testing time was 56 ± 29s and 65 ± 24s for the Humphrey Zeiss FDT and the smartphone FDT, respectively. All tests were considered reliable with a false positive and false negative score <33% on both exams.

Conclusions : Comparative testing of the smartphone FDT shows no significant difference when compared to the Humphrey Zeiss FDT. This technology is affordable and accessible and can be used in a variety of settings, especially in community and international glaucoma screenings. Ongoing studies are being performed to quantitatively compare the smartphone FDT to the gold-standard Humphrey Field Analyzer.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

The smartphone FDT consisting of an Android smartphone, virtual reality headset, and bluetooth remote.

 

Linear regression analysis for the Humphrey Zeiss FDT and the smartphone FDT.