The ability to augment, diminish, or otherwise alter one's perception of reality through the use of a computer.

Typically, it is the user's visual perception of the environment that is mediated. This is done through the use of some kind of electronic device which can act as a visual filter between the real world and what the user perceives, such as an Eyetap device.

Computer mediated reality has been used to enhance visual perception as an aid to the visually impaired. This example achieves a mediated reality by altering a video input stream light that would have normally reached the user's eyes, and computationally altering it to filter it into a more useful form.

It has also been used for interactive computer interfaces.

The use of computer mediated reality to diminish perception, by the removal or masking of visual data, has been used for architectural applications, and is an area of ongoing research (see for instance, here and here)