Authors: Yusuf Ahmed, Austin Pereira, Sylvie Bowden, Runjie B. Shi, Yan Li, Iqbal Ike K. Ahmed, Steve A. Arshinoff

Author Disclosure Block: Y. Ahmed: None. A. Pereira: None. S. Bowden: None. R.B. Shi: None. Y. Li: None. I.K. Ahmed: Membership on advisory boards or speakers’ bureaus; Zeiss (Consultant). S.A. Arshinoff: None.

Abstract Body:

Purpose: Visual Field (VF) testing is an integral part of the management and monitoring of glaucomatous change. Current VF testing technology is expensive, non-portable, and requires supervision by a trained technician. The Toronto Portable Perimeter (TPP) is an inexpensive, portable alternative perimeter that utilizes a personal smartphone and a virtual reality viewer to conduct VF tests. The purpose of this study is to compare the performance of the TPP with the Humphrey Field Analyzer (HFA) in VF testing.

Study Design: Multi-centre prospective cohort analysis.

Methods: Patients with suspected or confirmed glaucoma at Prism Eye Institute (Oakville, Ontario), York Finch Eye Associates (North York, Ontario) or the CNIB Mobile Eye Care Unit (Cochrane, Ontario) were considered for inclusion. Each patient performed consecutive VF tests on the same eye using the HFA SITA-Standard 24-2 test and TPP-Standard 24-2 test in random order. Bland Altman analysis and paired t-tests were used to compare the performance of the TPP to the HFA. The primary outcome was the mean difference in mean deviation (MD) between cohorts.

Results: 123 eyes from 77 patients were included in analysis. Average MD (±standard deviation) of the overall cohort using HFA and TPP VF testing was -3.99 ± 4.93dB and -4.27 ± 4.68dB, respectively. Bland Altman analysis showed good agreement between HFA and TPP tests of the same patient eye. The mean differences (95% confidence interval) between HFA and TPP for MD, Pattern Standard Deviation (PSD), Visual Field Index (VFI) and test duration were 0.28 dB (-4.19 to 4.75dB), -0.08 dB (-3.56 to 3.39dB), 0.5% (-11.3 to 12.3%), and 5.88 seconds (-87.6 to 99.4 seconds), respectively. Mean difference between the HFA and TPP tests for MD, PSD, VFI and test durations were not statistically significantly different. False positive rates on the TPP and HFA were statistically similar (TPP: 2.6%, HFA: 3.0%, p = 0.42); however, percentages of fixation losses were significantly lower (TPP: 12.8%, HFA: 20.8%, p<0.01) and false negatives were significantly higher (TPP: 10.1%, HFA: 4.3%, p < 0.01) on the TPP.

Conclusions: The results of this study demonstrate that MD, PSD, and VFI test results on the TPP are statistically similar to those measured on the HFA. Test time duration did not significantly differ between TPP and HFA tests. These results suggest that the TPP may offer a more accessible, lower-cost alternative to HFA visual field testing.