A pair of 3D glasses work because your eyes see slightly different views of the world. When you look at an object, your brain pieces the two images together, creating three-dimensional vision. The glasses do the same for a flat image.
The significant element involved with 3D imagery is the parallax effect. This is the horizontal distance between left and right images. When two related perspective viewpoints are presented, the image appears to be three-dimensional.
There are four basic types of 3D glasses. One method uses a separate display for each eye to mimic reality, while another uses shutters over each eye to trick the mind. Color filter glasses use a red and blue lens to highlight different colors on the screen. Polarizing glasses use a method of left and right circular-polarization to trick the eyes.
Research into the science of stereoscopy, invented by Sir Charles Wheatstone in 1838, led to the creation of 3D glasses. Over the years, entertainment became the primary utilization, most notably in feature films and rides.
In 2009, American Paper Optics produced one of the largest runs of 3D glasses for a single event. The company made 125 million pairs of glasses for an advertisement aired during Super Bowl XLIII.