Virtual reality brings some fantastic opportunities for people with disabilities. New experiences, therapeutic benefits, even accessibility for people who have better head control than hand control. But it also brings considerable new barriers, with great potential to lock people out from these benefits.
Some of the barriers that VR presents are unavoidable, there are people who will simply never be able to take part in VR as it currently exists. From the people who will never be able to overcome simulation sickness, to people who simply aren’t physically able to have a bulky device on their head.
But other barriers are avoidable, through the right design considerations - through accessibility.
It is still early days for this iteration of VR, so this post doesn’t aim to provide all of the answers or form a concrete set of guidelines. There will be issues that are not covered here, and still there’s huge room for innovation, discovering new and better design patterns.
It does however aim to ask some questions, point out a few VR-specific barriers to access, and show a few possible solutions, allowing you to include more people as a result.
Simulation sickness
“I've stopped buying or playing any game that only uses artificial motion due to motion sickness. I've tried them on and off for about 6 weeks now and every time I feel sick.”
Lord Wibbley, via Reddit
Simulation sickness occurs due to some of your senses telling your brain that one thing is happening, while other senses are busy telling your brain that something else is happening – a sensory mismatch between your visual system and your vestibular system. It is similar to motion sickness, but the opposite. Motion sickness occurs when your visual system says you are stationary but your vestibular system says you are moving. Simulation sickness occurs when your visual system says you are moving but your vestibular system says you are stationary.
Simulation sickness is the area of accessibility that has seen by far the biggest effort. Not really surprising, considering the role it played in the decline of the of the VR industry in the early 90s.
“The home version of the Sega VR was never released because it gave users motion sickness. As Tom Kalinske told Hyper in an interview, “We had great hopes for it in the nineties but the technology wasn’t there, plus almost everyone got sick from immersing.””
From Sega & VR – Ahead Of It’s Time
It is a prevalent and important issue. Some people will never be able to play due to it, regardless of how well designed the hardware or software is. Even just putting on a headset and looking around is enough to trigger simulation sickness in some people.
Some - but not all - people are able to adapt through acclimatisation. However I am sceptical about the degree to which that’s going to happen. There will be people who simply won’t go back for another try if their first experience is a bad one. The chance that it might not be so awful next time doesn’t seem like a compelling enough reason.
I’ve had an awful experience myself. I found myself in a situation where I was carrying out an accessibility audit on a VR game, and only had one session to cover everything in. After starting to feel the onset I had to force myself on through it for another half hour, to ensure all areas of the experience were covered.
Never do this!
As a result I was laid low for a whole two days afterwards, and still have ongoing bad effects from it over a year later. Over that past year I’ve regularly suffered from car sickness, something I hadn’t experienced since I was a child, and now find fast camerawork in movies and playing FPS games difficult too, neither of which I experienced before.
I’ve seen some other reports of the same long term effects from a bad experience, although they’re obviously uncommon and extreme cases. But you don’t need to have an experience that’s this bad to put you off.
And of course it’s not only important for the individual players’ experience. It’s important for the whole VR industry, from a PR angle. A well known example is the negative coverage of Resident Evil’s showing at E3 taking attention away from many positive stories.
For many people, simulation sickness can be avoided if the right design considerations are in place. The goal is to avoid your eyes giving you a sense of movement when your inner ear and so on are telling you that no movement is taking place.
Techniques include (but are not limited to):
Locomotion options that avoid a sense of movement that doesn’t match player movement
Keeping the camera in full control of the player at all times, and always controlled by head movement by default (although providing an extra option to use controller instead is helpful for motor accessibility)
Dynamically reducing amount of peripheral vision during movement
Giving the player a frame of reference (such as tracks or a cockpit)
Maintaining a constant horizon
Avoiding objects quickly moving towards/away/past the player (including large objects moving close to the player’s head)
Avoiding acceleration/deceleration
Maintaining constantly high framerate (minimum requirements currently vary depending on platform and research – 60fps, 75fps, 90fps – but it should always remain constant) and low latency (below 20ms)
Avoiding any kind of blur effects (particularly in peripheral vision)
Avoiding fast head movement (to reduce risk of the headset shifting during use)
Use of language, for example talking about comfort rather than illness, as just having the idea of simulation sickness in your head can make you more prone.
There are many other considerations and a great deal of literature covering them, so to save repeating it all, here are a few good ones:
Some simulation sickness considerations can be implemented as an integrated part of the experience, others can be implemented through options. These options have been seen in the form of a comfort mode from very early on. Such as in The Gallery: Six Elements, an early comfort mode that replaced free analogue rotational seated movement with snapping to fixed 30 degree increments.
“VR is all about options and VR Comfort Mode is an optional beginner mode that just so happens to be super comfortable to use in practice. Not everyone will love it, but its far less immersion breaking than running to the couch for a glass of ginger-ale :) Our aim is to give people plenty of options so that they can remain in the simulation for longer”
CloudHeadGames, via Reddit
Howe
