While the entertainment world has numerous virtual reality (VR) headsets for gaming and exploring, optometry has similar and exciting opportunities for use of this tech in visual field (VF), macular degeneration and objective testing.
COVID-19 has made us revisit many of our diagnostic technologies. Few patients today want to stick their heads in a dome that hasn’t been disinfected, which isn’t a simple task and could damage the device. Existing dome VF technologies require their own dark room, aren’t comfortable to sit for a significant amount of time and use monocular testing, which increases time and anxiety. These factors contribute to patient fatigue and can lead to a decreased sensitivity and reliability, resulting in multiple tests.1,2
VR Headset Technology
Head-mounted devices make VF testing more user-friendly. Devices such as HTC (Vive), Oculus (Olleyes), Heru’s VR headset and the Smart System VR Headset (M&S Technologies) are placed over the eyes and secured behind the head. The patient simply looks at a central target and the requested VF (10-2, 24-2 or 30-2) is measured in about three minutes per eye. There is also a screening VF that takes about 45 seconds. Some systems test binocularly since the patient can’t truly tell which eye is being tested in a VR headset, and most can also import data directly into an EHR system.
Some attributes I’ve found helpful include binocular vision testing to increase efficiency and active tracking. It’s important to have systems that don’t simply have a fixation target, but rather active pausing of the test when fixation is lost. For example, the Smart System VR headset target goes from red to gray when the internal cameras sense the patient’s eyes are not looking at the target, and testing automatically stops. Once the patient resumes fixation, the target turns red again and the test resumes. Also look for systems that include verbal cues through the headset to assist with testing and fixation.
Patients don’t typically lose a single point of vision in glaucoma, but rather a cluster or area that eventually leads to a nasal step defect or arcuate pattern. The Smart System VR headset provides an intriguing aspect called neighborhood cluster testing, which has been shown to increase efficiency and accuracy. The test detects larger clusters and each cluster is explored more closely, and the information from neighboring positions help define the shape and pattern of impairment.
Other Applications for VR
Many of these same systems not only perform VF testing but can measure visual acuity, color vision testing and contrast sensitivity. AdaptDx Pro (Maculogix), for example, can help diagnose AMD. Dark adaptation is a 5.5 minute test that, like VF testing, is typically reimbursed by insurance unless you use it as a screening device. Off-fovea light comes through the VR headset and the patient monitors light input to determine when adaptation occurs. Patients without AMD will typically adapt well before 5.5 minutes, which is a normal rod intercept. The system is sensitive enough to determine AMD three years before signs such as drusen are evident and can also be used to track disease progress. The manufacturer recently went out of business but the technology will survive in some fashion.
This VF device is another fascinating advancement that involves a short simultaneous bilateral exam (about three and a half minutes per eye) with automatic asymmetric reporting. The technology, from Konan Medical, is based on neurological (pupillary) response to stimuli and provides accurate results in faster time that reduce the need for retesting, and is simple to sanitize compared with bowl-shaped subjective VF devices.
24-2C, SITA Fast, SITA Faster and now VR technologies, as well as the new objective field testing, will change how we measure VFs. These systems already translate the data into clinically meaningful printouts we’re familiar with. There are variances among the technologies worth exploring, but VF—one of the tests least preferred by patients—is ripe for reinvention.
Dr. Karpecki is medical director for Keplr Vision and the Dry Eye Institutes of Kentucky and Indiana. He is the Chief Clinical Editor for Review of Optometry and chair of the New Technologies & Treatments conferences. A fixture in optometric clinical education, he consults for a wide array of ophthalmic clients, including ones discussed in this article. Dr. Karpecki's full list of disclosures can be found here.
1. Hudson C, Wild JM, O’Neill EC. Fatigue effects during a single session of automated static threshold perimetry. Invest Ophthalmol Vis Sci. 1994;35:268-80.
2. Barkana Y, Gerber Y, Mora R, et al. Effect of eye testing order on automated perimetry results using the Swedish Interactive Threshold Algorithm Standard 24-2. Arch Ophthalmol. 2006;124(6):781–784.