Computer-mediated reality refers to the ability to add to, subtract information from, or otherwise manipulate one's perception of reality through the use of a wearable computer or hand-held device such as a smartphone.

Mediated reality is a proper superset of mixed reality, augmented reality, and virtual reality, as it also includes, for example, diminished reality.

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, such as an EyeTap device or smart phone, which can act as a visual filter between the real world and what the user perceives. 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.

The long-term effects of altering perceived reality have not been thoroughly studied, and negative side effects of long-term exposure might be possible. Short term effects have been demonstrated with the eyestrain caused by computers.