Throwing up a new theory: Why AR / VR make you nauseated

“Depending on the content and technology, 20-95% of users typically experience some symptoms,” cautions a note issued by the VR/AR Association, or VRARA, an industry body whose members include Meta and Microsoft. The note was issued in 2021, but the problem persists.

What causes the side-effects? Essentially, they are a response to the technology’s attempts to force the brain to process stimuli received from two layers of reality at once. The disorientation this causes is called visually induced motion sickness, or VIMS.

“If there is a mismatch between the visual information and the hand movements then ‘surprise’ will result, and the human brain will need to adapt if future interactions between vision and action are to maintain their accuracy… The process of adaptation may cause difficulties — and these difficulties might be particularly problematic for children as their brains are not fully developed,” Mark Mon-Williams, professor of cognitive psychology at Leeds University, wrote, following a short-term study conducted on children, in 2017.

As has happened so often through history — think of the internet, radar, and the walkie-talkie — key breakthroughs could come via the US military.

In March 2021, the US Army awarded a $22 billion contract to Microsoft to build 120,000 custom HoloLens mixed-reality headsets. The idea was to use them in training programmes, and to then test them extensively to determine possible use-cases in the field. Could they be used, for instance, to offer soldiers visual additional input in real time?

The training-level rollout did not go well.

A 79-page report released last year by the Operational Test and Evaluation wing of the US Department of Defense (DoD) described “mission-affecting physical impairments” that included headaches, eyestrain and nausea. As much as 80% of soldiers reported some level of discomfort.

In July 2023, Microsoft sent DoD 20 new prototypes for testing. Results have been positive, is all the military will say. Specifics on the changes made remain under wraps, but these have included hardware improvements to make the headsets lighter.

What else might help ease the sense of disorientation and resultant side-effects?

One key factor could be a faster optical-refresh rate. That is the path gaming-focused computers and laptops are taking, with refresh rates of 144 Hz to 250 Hz now available on some screens, to render fast movement more smoothly.

Hertz, in this context, indicates the number of times a screen or display can draw a new image, per second. Currently, most mixed-reality headsets offer refresh rates of 60 Hz to 90 Hz. Faster is better, since the human brain processes moving images comfortably at speeds of about 120 Hz.

Apple is expected to focus on variable refresh rates for its upcoming Vision Pro headsets, by splitting visual input into two streams of data, for the display to meld into even frames.

The more closely AR and VR views mimic eyesight, the less blurring, disorientation and eye strain users will likely face from lagging or jagged frames, particularly as they turn their heads to “look around”.

Eventually, however, what will also be needed is time. It will take practice to train the brain and eyes to accommodate spurts of augmented-reality immersion. The experience will likely remain variable — as it has been with other intense sensory experiences such as train travel, flight, and adventure sports.

Some users may always get a bit VR-sick. Perhaps there will eventually be a pill to pop, to help tackle VIMS over short periods.

For now, take regular breaks. Listen to your brain and body. Rest. That isn’t just common sense; it’s advice from Microsoft’s health and safety guide for HoloLens.