The Health and Safety Warnings accompanying the Oculus Rift say the VR headset not be used by children under the age of 13, partly because the hardware isn't sized for smaller heads, and partly because "younger children are in a critical period in visual development."
Sony says the PlayStation VR headset is not for use by children under the age of 12. HTC doesn't give any age cutoff for the Vive, but cautions owners not to leave the device within reach of younger children, adding: "If older children are permitted to use the product, then adults should monitor them closely for any negative effects during and after their use of the product. Do not allow older children to use the product if negative effects are observed. Adults should also ensure that older children avoid prolonged use of the product."
However, these varying guidelines may not reflect differences in the technology being used so much as they reflect differences in the posteriors from which they're pulled. Speaking with GamesIndustry.biz last week, University of Leeds Professor of Cognitive Psychology Mark Mon-Williams said there was no solid basis for any such recommendation.
"We just don't know what happens [long-term]. It might be that the system can adapt quite happily and there are no issues at all, or it may be that it causes long-term problems, long-term deficits"
"These are just arbitrary cut-offs plucked out of thin air," he said. "There's no science to back them up, and it's all conjecture."
That's not to say the VR headsets are fine for kids of all ages, but neither is it a suggestion for parents to forbid their children any VR experience entirely.
"The problem is you get two extremes, neither of which is helpful," the professor said. "The one extreme is, 'Virtual reality will make your kids go blind, don't use it,' which is scientifically inaccurate, but also is just putting your head in the sand. Virtual reality is here and it's here to stay. At the other end of the extreme, you've got people saying, 'There are no issues here, let's just ignore known problems.' Which again, is really not helpful... So the end for me is the sensible approach, which is to say we know about physiology, we know theoretically where some of these problems could crop up, so let's work together to make sure the systems people are using can be used helpfully and safely."
So just what are those theoretical problems?
"We know these [stereoscopic displays] can place the system under short-term pressure," he said. "We just don't know what happens [long-term]. It might be that the system can adapt quite happily and there are no issues at all, or it may be that it causes long-term problems, long-term deficits... It may be that young children actually have less problems than old because there's more flexibility in the system. Or it may be that because there's more flexibility in the system, it's more likely to cause long-term difficulties. The science just isn't there to allow us to answer those questions."
Professor Mon-Williams's research into virtual reality and its potential problems goes back to the last wave of interest in the field and the 1990s. But for all that's changed with the technology in the decades since, one of his biggest concerns has gone essentially unaddressed. Ordinarily, when you look at something very close to you and then look at something in the distance, your eyes adjust where they're looking and how far away they're focusing accordingly. But when you do the same in virtual reality, where the world is still just an image on a screen inside your headset, you're still focusing right in front of your face, even when the object you're looking at seems to be way off in the distance.
"I really hope this time around, it doesn't become polarized and sensationalized, and what we can do--industry and academics--is work together"
"The real issue is when you put somebody in a three-dimensional stereoscopic world where you want them to look at objects that are six meters away, three meters away, and 20 centimeters away," Professor Mon-Williams said. "That large range is going to drive big differences in where the eyes need to be positioned relative to where the eyes need to be focused. So it's an intrinsic property of stereoscopic displays, but just because a display is stereoscopic doesn't mean it necessarily will place pressures on the system. The pressures come when that stereoscopic range gets to a certain magnitude."
Knowing this, what's the best course of action going forward? For the moment, that might boil down to academics continuing to research the problem and game developers designing their VR titles to have a relatively narrow range in which users need to focus their vision. From a bigger picture perspective, it means developers and academics will need to work together to design and engineer systems which either don't have the same problems, or circumvent them effectively. That might be the same solution he would have suggested in the '90s, but Professor Mon-Williams said he's more likely to find cooperative voices in the field today.
"One thing slightly different from 20 years ago is that the companies themselves in the industry at that stage didn't want to acknowledge that anything could possibly be amiss, that there could possibly be any issues with introducing a new technology," he said. "Which is just fantastical. I mean, what new technology doesn't have potential issues? What excites me at the present moment is that we can deal with the issues. This could be one of the first technologies where we could iron out the teething problems and get all the benefits without any of the potential side effects. That's what I really hope we can achieve over the forthcoming years."
Another difference between the climate now is that video games themselves are a less contentious cultural subject. For most of the past 20 years, video game violence was a highly polarized debate, both in academia and in wider society. It was a debate with parents groups and politicians on one hand, and the industry and players on the other. These days, since we have ratings systems with wide approval and effective parental controls built into major platforms, hand-wringing about the level of violence in games seems more likely to come from within the industry itself, while legislators have turned their attention to more pressing concerns.
"There's an aversion to any new technology, isn't there? And people love a sensational story, either 'Oh, this is going to change everything we're doing' versus, 'Oh this is terrible. It's the new evil,'" Professor Mon-Williams said. "And again, the truth to all this lies somewhere in the middle. So I really hope this time around, it doesn't become polarized and sensationalized, and what we can do--industry and academics--is work together. Because when technology works well, it makes our lives better, and makes the world a better place."