Why do we need 3D glasses?

First of all, 3D glasses make it possible to see the spatial depth of the two images that stereoscopic techniques present to the viewer’s left and right eye. Signals from the two images need to reach the brain simultaneously yet by separate channels which is made possible by filtering in the 3D glasses.

There are as many kinds of 3D glasses as there are stereoscopic techniques. The types most commonly in use are anaglyph, polarization and shutter techniques.