Second Life makes me sick. Literally. When I enter its 3D environment, my brain can’t believe what my eyes are seeing and, within seconds, I start to feel woozy. By the end of 10 minutes, I have the start of a nasty headache. If I stay longer than that, the vertigo when I finally return to the real world is enough to knock me off my chair.

You see, I suffer from simulator sickness, a type of motion sickness induced by 3D virtual environments.

I’m not alone as a sufferer. Studies indicate that up to 60 percent of fighter pilots suffer from at least one symptom of simulation sickness when training on simulators, and these are people who’ve been handpicked for resistance to such a reaction. There haven’t been many studies of the broader population, but some research points to 80 percent of the population being affected to some degree. For some of the sufferers, the symptoms are mild: a little dizziness after playing a 3D game for a couple of hours; a touch of nausea; eyestrain. For others, like me, the effects can be dramatic and longlasting.

Traditional wisdom has been that simulator sickness strikes when the visual motor cues you receive don’t jibe with the physical motor cues. The folk over at the Human Interface Technology Lab (HITLab), think that may not be the case. They suggest that it’s not the conflicting motion cues that are the problem, but rather the conflicting stationary cues. Our brains search for consistent stationary objects in a scene to provide stability; when those objects (known as ‘rest frames’) are absent or changing, things can get scrambled in your head.

A new class of disabled

The computing world is increasingly first-person, 3D. Take a look at the top 50 games. Check out the popularity of 3D online worlds, such as Second Life. Surf the research sites of Microsoft and other software developers. 3D environments abound. In games, 3D designs dominate almost to the exclusion of other, less immersive interfaces.

Now, if suffering from simulator sickness meant nothing more than being excluded from playing Myst or Halo, it’d be a shame, but certainly not calamitous. The trouble is, that’s just the start.

Take Second Life. It’s partly a game, yes. It’s also an experiment in where the web is heading. That’s why companies are setting up shop within the virtual world; it’s why some organisations hold meetings and training sessions there. And you can bet that as our hardware gets more powerful and the software more refined, online 3D environments will start appearing with increasing regularity.

The same thing is happening with operating systems and general applications. Wander over to Microsoft Research – one of the most interesting parts of the Microsoft site, by the way – and you’ll find a bunch of projects based on 3D manipulation and technologies.

Those games developers who show any awareness of simulator sickness tend to shunt the problem aside. It’s too much work to find a solution and, after all, “no-one’s making them play the game”.

But what happens when it’s not a game? What happens when your company announces it’s holding staff meetings in Second World from now on? Or when Microsoft or Apple release an immersive operating system? Then it’s no longer a matter of “tough luck, you can’t play”; it becomes a matter of disability. If the limited research so far is correct about the number of people likely to be affected, the ranks of the virtually disabled will be huge.

Locked out

All up, I spent about 25 hours in Second Life. I knew it was too long but I felt I had to do it because I’d been commissioned to write an article about the online world for Australian PC User.

After a 20-minute stint in Second Life, I’d feel sick. But 20 minutes isn’t nearly enough time to explore the world, so I’d dive back in for longer to do more research. Even though I broke those 25 hours of virtual experience into smaller chunks, by the time I’d completed my article I had experienced severe nausea, headaches, eyestrain, disorientation, and dizziness which didn’t dissipate entirely for almost a month. Second Life is a fascinating place, but I won’t be returning. I just hope I won’t be locked out of more and more of the digital landscape. I hope you won’t be, either.