recently told Gamasutra that prolonged exposure to 3D displays is "not likely to cause any permanent harm to vision." Unless, of course, you're watching on Bravia's controversial new set, the Eye-Poker 3D 5000.
Borchert explained that 3D displays aren't completely without risks, stating "there are people who get uncomfortable with it, and get eye strain or headaches, or on much rarer occasions, a sense of imbalance or nausea, but there's no evidence it can cause permanent harm to your vision or use of both eyes together or anything like that." So, there you go. It probably won't make you blind, but it may make you feel like vomiting every time you use it. Man, the future's gonna be awesome.