Children under seven who play Nintendo's 3DS likely won't discover whether the handheld has damaged their eyesight until years later.
That's according to University of Cambridge graphics and imaging expert Dr. Neil A Dodgson, who told CVG that Nintendo is simply "covering itself" with advice that kids under seven don't play the 3DS with 3D images turned on.
"With regard to children under seven [playing 3DS], the answer is that we just do not know whether they will have a particular problem or not," Dr. Dodgson explained.
"I imagine that any problems for young children would be common to almost all 3D systems, as almost all of them cause convergence/focus conflict."
He continued: "But we do not know if there is actually a problem for young children. Intuitively, one might expect that children should not be exposed for long periods until their convergence/focus mechanisms have been fully trained, but I do not know the age by which that is supposed to have happened.
"The problem with finding out for sure is that no-one is going to perform experiments on children if there is the slightest chance of lasting damage. So the company is covering itself.
"We will only really know if there is a problem if we get a spate of cases where young adults find that they have eyesight problems that can be statistically correlated with excessive use of 3D at an earlier age," he said.
Earlier this week Kid Icarus designer, Masahiro Sakurai - who's been working on the 3DS for some time - revealed that he's designing his game specifically with avoiding eye strain in mind.
"In my experience of development and actually using [3DS], when you have a lot of objects flying towards the user I find that it's more likely to cause eye strain so during development I'm using objects moving away from the user which doesn't have that effect," he said.
We recently managed another hands-on session with the 3DS, but of course we didn't play it anywhere near enough to gauge whether eye strain becomes a problem or not.
It's a case of wait and see, we reckon. (No pun intended).