Engineers and scientists use Augmented Reality Visors to provide stereoscopic views of CAD schematics. These systems are also used in the maintenance of complex systems, as they can give a technician what is effectively "x-ray vision" by combining computer graphics such as system diagrams and imagery with the user's natural vision. There are also applications in surgery. A combination of radiographic data (CAT scans and MRI imaging) can be combined with the surgeon's natural view of the operation.
An early Augmented Reality Visor prototype was KARMA (Knowledge-based Augmented Reality for Maintenance Assistance) to show simple end-user instructions for how to repair and service a laser printer by using a ghost image on the real background.
