I think the technology used with these glasses is:
If you were looking at a screen with 60 frames per second. 30 frames will be for your left eye & 30 frames will be for your right eye. The frames alternate left,right,left,right,left,... When a frame for the left eye is shown, your glasses will block the view for your right eye and when a frame for the right eye is shown, your glasses will block the view for your left eye.
If you don't use those glasses you'll see double.
Also note that even if the display is set to 60 fps, your eyes will only see 30 fps each. Display has to be increased to 120 fps if you want to see 60 fps with each eye.
Edited, Jun 16th 2010 8:12pm by RedGalka