While stereoscopic 3D continues to be promoted as the next big thing in home theater technology, the long term health consequences of it are not clear. Some people - myself included - have complained of headaches, blurry vision, and other side effects.
Sony, no doubt preferring to play it safe, has issued a warning saying these problems are not to be taken lightly. The latest Playstation 3 Terms of Service statement advises that anyone who experiences "eye strain, eye fatigue or nausea" should turn off 3D immediately. Players can begin using the technology again when discomfort subsides, however.
It isn't clear what research Sony's disclaimer is based on, but the company isn't alone in its caution. Nintendo has stated that the new 3DS will carry a recommendation that children under the age of seven should only use the device in 2D mode. Samsung has also stated that watching 3D content isn't advisable if you "need sleep or have been drinking alcohol."