Binocular inhibition occurs when binocular performance is less than monocular performance. Sighting is optical, and carried out through an M112/3 combined monocular telescope and binocular periscope. Depth perception results from many monocular and binocular visual clues. Games are viewed through a binocular eyepiece and controlled using an affixed gamepad. Professional activity may involve operating stereoscopic instruments such as a binocular microscope. In industrial use, binocular microscopes are common. David Brewster developed a stereoscope with lenses and a binocular camera in 1844. Optometrists and/or orthoptists are eyecare professionals who fix binocular vision problems. This causes loss of depth perception and binocular vision. Abnormalities with this can lead to binocular vision problems. This ultimately forms the physiological basis of binocular vision. A canonical example is its use in binocular vision. It had retractable claws, agile joints for climbing, and binocular vision. IPD is also used in binocular vision science. A horse will raise or lower its head to increase its range of binocular vision.