Remote longitudinal monitoring of glaucoma using virtual reality-based oculokinetic perimetry

ABSTRACT

Purpose: Virtual reality-based oculokinetic perimetry (VR-OKP) is a mobile, short, screening visual field test. The purpose of this study is to examine whether VR-OKP could be implemented in a remote fashion and used to assess the stability of the visual field. Methods: Glaucoma subjects with known glaucomatous defects who had taken an inperson VR-OKP test in 2019 were re-enrolled and underwent the same test remotely in 2020. An exit survey comparing patients' preferences for visual field testing was also conducted remotely. Subjects underwent Humphrey visual field 24-2 (HVF) testing within 3 months of VR-OKP both in 2019 and 2020. For unadjusted comparisons between HVF and VR-OKP, we compared mean sensitivities and fraction of points. A non-parametric bootstrap analysis that resampled eyes with replacement was done to calculate the 95% confidence interval of the Spearman correlation coefficient between HVF sensitivity versus VR-OKP fraction seen at each point of the 54 test locations. Results: The cohort consisted of 19 eyes of 11 patients (55% female, 73% Caucasian, 27% Asian, mean age 61.4 ± 12.6 yrs) with moderate to advanced glaucoma (2020 average HVF mean deviation -4.23 dB ± 5.12). VR-OKP from 2019 to 2020 had a decreased mean percent change of -6.31% ± 17.22 (p=0.13) compared to HVF testing from 2019 to 2020 which had an increased mean change of mean deviation of +2.41 dB ± 1.35 (p<.00005). The Pearson's Correlation Coefficient between 2019 VR-OKP fraction seen and 2019 HVF mean sensitivity was 0.74, while it was 0.56 in 2020. Spearman correlation coefficients of HVF sensitivity vs VR-OKP fraction seen at each point ranged from -0.01-0.86 (median = 0.33). Subjects found VR-OKP to be as comfortable as HVF (p=0.8) and less fatiguing (p=0.03). Conclusions: This study highlights the feasibility of a remote option for visual field assessment. The correlation between VR-OKP and HVF in 2019 was higher than in 2020. One explanation is that the 2019 test was taken with in-person instruction, whereas the 2020 test was administered remotely. While the mean percentage change in VR-OKP was non-significant, the 2019 to 2020 change in HVF was statistically significant and showed improvement, which may be due to long term fluctuation. This short VR-OKP test is less fatiguing to patients, can detect non-progression even when taken at home, and could potentially be deployed to decrease patients' risk of COVID-19.