A Comparison of Perimetric Results from a Tablet Perimeter and Humphrey Field Analyzer in Glaucoma Patients

Abstract

PurposeTo determine the correlation between the perimetric outcomes from perimetry software Melbourne Rapid Fields (MRF) run on an Apple iPad tablet and those from the Humphrey Field Analyzer (HFA).MethodsThe MRF software was designed with features including variable fixation and fast thresholding using Bayes logic. Here, we report a cross-sectional study on 90 eyes from 90 participants: 12 had normal optic nerves and 78 had glaucoma with various degrees of visual field loss (41 mild and 37 moderate-severe). Exclusion criteria were patients with worse than 20/40 vision or recent intraocular surgery. The visual field outcomes of MRF were compared against those returned from the HFA 24-2 SITA standard. Participants were tested twice on the MRF to establish test–retest repeatability.ResultsThe test durations were shorter on MRF than HFA (5.7 ± 0.1 vs. 6.3 ± 0.1 minutes, P < 0.001). MRF showed a high level of concordance in its outcomes with HFA (intraclass coefficient [ICC] = 0.93 for mean defect [MD] and 0.86 for pattern deviation [PD]) although the MRF tended to give a less negative MD (1.4 dB bias) compared with the HFA. MRF also showed levels of test–retest reliability comparable to HFA (ICC = 0.93 for MD and 0.89 for PD, 95% limits of agreement −4.5 to 4.3 dB).ConclusionThe perimetry results from the MRF have a strong correlation to the HFA outcomes. MRF also has test–retest reliability comparable to HFA.Translational RelevancePortable tablet perimetry may allow accurate assessment of visual field when standard perimetry machines are unavailable or unsuitable.

Performance of iPad‐based threshold perimetry in glaucoma and controls

“…The results from this study for scotoma detection and reproducibility are generally in agreement with those of the software developers . In both studies MRF global indices correlate well with HVF and ICC for test–retest are favourable.…”

“…Since this was an independent study as opposed to that conducted by the inventors of the application we did not have a preconceived idea of variability or sensitivities on which to base sample size. However, our results do seem to be fairly consistent with those of Vingry’s et al . In addition, we do not have access to the algorithms for MD, VFI and PD for the MRF software as these are proprietary and as such we are unable to comment on how these compare to HVF.…”

“…It is important to note that the points included in the various regions differ between the two studies and may account for some variability. Test–retest ICC for the regional mean threshold also varied compared to Kong et al . Further investigation with a larger cohort of glaucoma patients with a wide variety of scotoma sizes and locations would be useful to further elucidate MRF test–retest variability.…”

“…The temporal zone was not analysed as both tests had high variability in this region due to blindspot shifts. These zones were modified from those used by Vingrys and Kong, as we sought to include points in the mid‐peripheral regions that were more closely related topographically to HVF test points (see Fig. ).…”

“…The Nepal Study found that the Visual Fields Easy test procedure is a portable, fast, effective procedure for detecting moderate and advanced visual field loss . The Melbourne Rapid Fields program (MRF), is an improved thresholding version of the software developed by the same research group, and has recently been reported by the software developers to show good sensitivity and specificity in mild, moderate and severe glaucoma . A recent paper reports on a simulation of MRF results based on what might be expected in home‐based testing and concludes that more frequent testing could improve detection of change even with poor compliance …”