But TV receivers that use what is called a passive glasses system are costly.

VOA: special.2010.01.26

A signal from the TV tells each side of the glasses when to turn on and off, showing each eye slightly different images that create the sense of depth.

VOA: special.2010.01.26

(Movie Sound) Cameron also pioneered a realistic 3D technology that requires the audience to wear special glasses;

VOA: standard.2009.12.19

"Someone said that he had made a cellphone call following the quake but the monsignor was holding a pair of glasses in his right hand.

VOA: standard.2010.01.20

The centers are run by an ophthalmic assistant who is trained to conduct a full eye examination, administer diagnostic tests, treat simple ailments and prescribe glasses.

VOA: standard.2010.05.25