Comparison of Perimetric Outcomes from a Tablet Perimeter, Smart Visual Function Analyzer, and Humphrey Field Analyzer

Abstract

The tablet-based Melbourne Rapid Fields (MRF) visual field (VF) test and the IMOvifa Smart Visual Function Analyzer (SVFA) are portable perimeters that may allow for at-home monitoring and more frequent testing. We compared tablet and SVFA results to outputs from the Humphrey Field Analyzer (HFA) 24-2 Swedish Interactive Threshold Algorithm (SITA) Standard program. Observational cross-sectional study. Adult participants with a diagnosis of glaucoma, suspected glaucoma, or ocular hypertension seen in the Massachusetts Eye and Ear glaucoma clinic were enrolled. All participants were reliable, experienced HFA testers. Participants were tested with the SVFA and HFA. Study staff also trained participants on the MRF tablet with instructions to take weekly tests at home for three months. VF results from the three devices were compared. Mean deviation (MD), pattern standard deviation (PSD), reliability parameters, point sensitivity. 79 participants (133 eyes) with a mean age of 61 ± 13 years (range 26-79) were included; 59% of the participants were female, and the mean HFA MD was -2.7 ± 3.9 decibels (dB). The global indices of MD and PSD did not significantly vary between HFA and the two novel devices, except that the tablet VF reported a 0.6 dB higher PSD compared to HFA (95% CI for difference between HFA and tablet = [0.27 dB to 1.02 dB], P < 0.001). However, tablet and SVFA sensitivities significantly differed from those of the HFA at 36 and 39 locations, respectively, out of 52 locations. Relative to HFA, the tablet overestimated light sensitivity in the nasal field while underestimating the temporal field. The SVFA generally underestimated light sensitivity, but its results were more similar to HFA results compared to the tablet. While average MD values from the two novel devices suggest that they provide similar results to the HFA, point-by-point comparisons highlight notable deviations. Differences in specific point sensitivity values were significant, especially between the tablet and the other two devices. These differences may in part be explained by differences in the normative databases of each device as well as how MD is calculated. However, the tablet had substantial differences based on location, indicating that the tablet design itself may be responsible for the differences in local sensitivities.