M&S Technologies News
M&S Technologies News
Visual Fields in Virtual Reality – A Technological Leap
Paul Harris, OD, FCOVD, FACBO, FAAO, FNAP
Professor, Southern College of Optometry
The use of technology has been altering the landscape of practicing optometry at an ever-increasing pace. However, some things have stayed the same so long it’s hard to imagine them ever changing. The visual field is one that has been the same for quite some time.
After transitioning from the Bjerrum tangent screen and bowl perimeter to automated visual fields, the mental picture is always the same. A patient sits in a small dark room with an eye patched and head craning forward onto the head and chin rest with a lens holder in front of the eye being tested. They sit with the clicker in hand, responding ad nauseum to the lights coming on and off across their visual field, while noises associated with the inner workings of a machine sound off, making this test one that would appear on our patients list of tests they would prefer to never do again!
Well, Virtual Reality (VR), when mated with the advanced Tobii eye tracking, is blowing this space wide open. The PICO headset is worn over just about any conventional eyewear (maybe not some of Elton John’s more wild frames). And, the Tobii eye tracker can be calibrated in just a few seconds of following a moving target in the headset. Once done, the visual field testing can begin.
Immediately, the patient will appreciate not wearing the eye patch. With traditional perimetry, patients tend to alternate between opening and closing the patched eye in order to concentrate with their uncovered eye. When testing the visual field in VR with both eyes open, there is a relaxation that comes over a patient that I never experienced under conventional testing. This relaxation reduces tension and actually allows the testing to flow more easily and get completed faster with more confidence that it is being done correctly.
Another benefit of the VR goggle being attached to your head is that patients don’t have to sit like a statue. They can move in their chair, pivot their head slightly, reposition in their chair if need be, all while continuing to respond to the lights as they come on. This is especially important for older patients with mobility and posture difficulties who can struggle with traditional perimetry exams. A key improvement you notice right away is that there is no reason to plot the blind spot. That was an exercise mostly to check if the patient was positioned correctly, see if they were capable of taking a visual field and find out how compliant they would be during testing. But, while using a VR headset with eye tracking, practitioners can get right to the testing. The device only shows a peripheral target when it knows for sure that the person is looking at the center target. No more having to look at gaze tracking data and determine if you had a cooperative patient or not. If the patient looks away to “explore,” the system waits for them to get back to the fixation point with a mild reminder. Once back, the test proceeds again.
One of the nicest parts of taking the visual field in the VR setup is the ability to automatically trigger the 2-eyes at the same time testing choice. Here, instead of presenting points all in front of one eye and stopping and then doing the other eye, the device randomly presents a point to one or the other eye as needed to complete both fields in one continuous sitting. By moving back and forth between the eyes, the person’s experience is not single-sided, but is more of a unified look into the open space in front of them, which is much more comfortable. Comfort equals increased reliability, which will translate into better optometric care. Typically, the time to complete the visual field is significantly shorter than doing each eye separately.
Thank you to M&S Technologies for providing us their Smart System® VR Headset (Pico) to test.