Depending on how you look at it, Nintendo is taking a pretty big risk with the introduction of the 3DS. Even though there is a slider to turn down the 3D effects, this is a handheld meant for games to be played in 3D. Not everyone can view 3D, and not everyone likes viewing it, so there’s already a segment of the market Nintendo cannot cater to.Now some new guidance (Japanese) has been put out by Nintendo for young kids using the 3DS, and for the regularity of breaks when using the device. In both cases, play seems more limited if you want to stop your eyes getting too tired or your vision to be impacted.In the case of young children (under 6), Nintendo suggests they don’t use the 3DS at all to play 3D games. 2D viewing is fine, but 3D is a big no-no. This is because such young eyes are still developing so viewing 3D may be detrimental to that continued development. Parents will find controls to stop 3D being displayed if they do intend on buying a 3DS for a child in that age group.As for everyone else, Nintendo used to state that a break every hour was recommended on previous 2D devices, but with the 3DS that has been cut in half to 30 minutes. This is due to viewing 3D content making your eyes tired more quickly. Even 30 minutes may be too long, with a break suggested at the first signs of you not feeling great.While the 3DS is sure to be a hit when it launches in March, the decision to go 3D does bring with it a few extra limits. Will those same people who got sick watching Avatar in 3D be unable to stand more than a few minutes of 3DS play? Or will it be a completely different type of person who suffers the ill effects?One thing’s clear, this is the first Nintendo hardware that may not be universally playable.Read more at KotakuMatthew’s OpinionI don’t think anyone takes any notice of the guidance given for any piece of electronic entertainment. When was the last time you played a DS game and kept an eye on the clock for a break every hour?If anyone is going to get sick playing on a 3DS it will be after a purchase has been made. Hopefully Nintendo’s 3D slider will allow for such sickness to be controlled or removed completely. If it can’t then we’ll hear a few complaints, but Nintendo must know the majority of players will be happy and sickness-free.The issue of tired eyes occurring quickly isn’t going to have an impact on sales, but it could make playing for long periods of time pretty tough. Once you have really tired eyes it’s difficult to carry on looking at the screen. That may not be a bad thing, forcing kids to go and do something else for a while.