Standard automated perimetry (SAP) is the gold standard for detecting and evaluating pathology or dysfunction in the visual pathways, but the technology is prone to patient-related artifacts. Patients may be unable to maintain proper head position, lose their concentration or fall asleep during the test, for example, resulting in inaccurate results; the test also requires “conscious decision making in identification of near-the-threshold-level stimuli,” note the authors of a recent study on an alternative technology called the VisuAll (Olleyes). The study was supported by an unrestricted grant from the manufacturer.
The device is a head-mounted perimeter with screens positioned 60.5mm in front of each eye; no eye patching is required for testing. A study published in The Journal of Glaucoma that compared the performance of the VisuAll with the Humphrey Field Analyzer (HFA) in glaucoma patients and healthy controls found a moderate-to-strong correlation between the two.
The prospective observational study included 50 eyes of 25 healthy subjects and 52 eyes of 26 patients with controlled mild or moderate glaucoma. All patients underwent visual field testing with both the VisuAll and the HFA (24-2 VF).
Researchers compared the mean sensitivity of the two devices as well as mean sensitivity of all quadrants and found a significant correlation in both the normal group and the glaucoma group. For discriminating between normal and glaucomatous eyes, the VisuAll’s mean sensitivity was 0.98 while the HFA’s was 0.93.
The researchers concluded that the VisuAll showed high diagnostic performance and had “excellent correlation” with standard automated perimetry in their study groups. They believe the device has potential, noting that the VisuAll improves patient comfort and may decrease test-induced fatigue and help patients with cervical or spinal disease, weight issues and body hiatus, all of which make HFA testing difficult. Its main limitations are those inherent to automated perimetry, the researchers noted.
“It will also allow visual field testing for hospitalized or bedridden patients,” the researchers added. “Portable visual field tests have great potential in the delivery of good-quality vision care for glaucoma patients in situations where access to standard perimetry machines is difficult and for special situations when patients are required to keep a social distance.
Razeghinejad R, Gonzales-Garcia A, Myers JS, et al. Preliminary report on a novel virtual reality perimeter compared with standard automated perimetry. J Glaucoma. 2021;30(1):17-23.