For as long as content has been displayed on a screen, parents have been telling kids not too sit to close. To blink. Or maybe not stare so hard. All of this in hopes that maybe, just maybe, their child's vision wouldn't get messed up before life eventually degraded them naturally. It looks like Nintendo is going to go ahead and step forward and say that, for kids that are six years or younger at least, using the Nintendo 3DS for extended periods of time with the 3D turned all the way on is dangerous for your kid's eyes.
According to the company, kids under six just shouldn't use the full 3D ability of the 3DS, because their eyes are still in the development stage. And thanks to the stereoscopic 3D that the machine uses, and the fact that a different image is thrown at the user's eyes, it "has a potential impact on the growth of children's eyes." Of course, having the warning is one thing, and parents can only do so much, so Nintendo has added a parental lock on the device, which will turn off the 3D capability of the portable gaming unit when the time is right.
This type of warning for younger children, when 3D is involved, isn't new. Sony has made the same kind of warnings in the past, saying that a child should be seen by an eye doctor first to determine whether or not they're ready for the use of the technology. Of course, considering the device is for the family, and many families include smaller children, this seems like a pretty sizable hill for the company to climb.