Medical advice: beware using green red paper glasses too many hours. An extensive usage can cause problems. (Don't watch a TV series hours and hours using them )
p.s. i remember reading about it years and years ago, curious
       
Yeah, it's me Dj Barth "One TrueBlue to rule them all, One Browser to find them,
One TB CFW to bring them all and in the Internal HDD bind them
In the Land of BarthMordor where Modding lie"
Anaglyphic 3D gives me a headache if I use it for too long so I think you may be right that it is not great if used for too many hrs.
Stereoscopic 3D makes me feel a bit weird if I watchstuff for more than 3 or 4 hrs as well
...and jerking off to 3D pr0n causes more medical problems!
Couldn't resist saying that, but on-topic to Barth's point, he is right - hell even the 3DS comes with a medical warning.
Instead of me being a complete and total dick and a prick, I should be on my best behaviour!
Yeah, it's me Dj Barth "One TrueBlue to rule them all, One Browser to find them,
One TB CFW to bring them all and in the Internal HDD bind them
In the Land of BarthMordor where Modding lie"