IMO visual function analyzer (IMOvifa), a binocular perimeter, has similar output to the Humphrey Field Analyzer (HFA), but reduced the measurement time.
The purpose of this study is to evaluate the performance of IMOvifa, a perimeter that performs binocular visual field (VF) testing, and to compare its results with standard automated perimetry.
All patients underwent HFA 24–2 SITA-Fast and IMOvifa 24–2 AIZE-Rapid on the same day. Mean deviation (MD), pattern SD (PSD), foveal threshold, and visual field index (VFI) were compared between the 2 perimeters using Wilcoxon signed-rank tests, Pearson correlation, and Bland-Altman plot. Measurement time for performing VF for both eyes was also collected for each device.
In this cross-sectional study, 138 eyes (including 25 healthy, 48 glaucoma suspects, and 65 primary open angle glaucoma) of 69 patients were evaluated. Measurement time was significantly faster for IMOvifa compared with HFA (256 vs. 419 s, P<0.001). No significant differences were seen in MD and VFI between HFA and IMOvifa (both P>0.05). Significant differences were seen in mean PSD 3.2 (2.7, 3.6) dB for HFA versus 4.1 (3.5, 4.6) for IMOvifa (P<0.001), and foveal threshold 33.9 (33.1, 34.6) dB for HFA versus 30.6 (29.3, 31.9) dB for IMOvifa (P<0.001). Pearson r was strong for MD (r=0.90, P<0.001), PSD (r=0.78, P<0.001), and VFI (r=0.94, P<0.001). The mean difference (95% limits of agreement) was −0.1 (−3.8, 3.5) dB for MD, −0.4 (−3.4, 2.5) dB for PSD, and 0.1 (−8.9, 9.1) dB for VFI, respectively.
IMOvifa reduced measurement time by 39%. MD, PSD, and VFI values for IMOvifa showed good agreement with HFA SITA-Fast strategy. This perimeter reduced fatigue for both patient and examiner. Additional studies are needed to determine whether it will be useful for routine VF testing.