Virtual reality glasses or goggles are becoming increasingly popular in the gaming and entertainment spheres. They are lighter and more comfortable to wear than the standard head mounted display (HMD) and many of them incorporate a range of interactive devices.

Examples of these include audio, video and head tracking.

These glasses behave in a similar way to a pair of 3D goggles in that they display two images. Ordinary glasses show a single image but 3D and virtual reality glasses contain polarised lenses which show two images, one per each eye. These images appear to give an illusion of depth which is a particular feature of CAVE environments.

The technical name for this is stereoscopy.

More advanced versions of these glasses contain head tracking systems. This system is connected to a computer which sends signals to adjust the images seen by the wearer as they move around their environment. Once again, this is a particular aspect of CAVE fully immersive virtual reality.

These glasses enable the wearer to see three dimensional images which give an illusion of depth of perception. For example, if the wearer is using virtual reality for architectural purposes then they will be able to view a building at different angles, and walk through or around it.

Many types of glasses contain a tracking system which maps the wearer’s movements and adjusts the images accordingly. Each time the wearer moves his head, walks in a particular direction or takes some other form of action, the scene in front of him changes as he does so.

The tracking system is connected to a computer which adjusts these images so that the wearer is shown a realistic environment with a realistic depth of perception. The tracking needs to be as accurate as it can be or else the illusion breaks down.

The glasses enable the wearer to see two separate images which the brain combines into one. This is what gives the illusion of 3D depth. This is often accompanied by video and/or sound which add to the experience.

The aim is to present the wearer with a world which is realistic and behaves in a similar way to the real world. Any delay or latency will cause a disconnection between the two and in some cases, feelings of motion sickness. This then disrupts their experience.