Editing Diplopia (section)

=== Voluntary ===
Some people are able to consciously uncouple their eyes, either by overfocusing closely (i.e., going cross-eyed) or unfocusing. Also, while looking at one object behind another object, the foremost object's image is doubled (for example, placing one's finger in front of one's face while reading text on a computer monitor). In this sense, double vision is neither dangerous nor harmful, and may even be enjoyable. It makes viewing [[stereoscopy|stereogram]]s possible.<ref>{{cite web | url = http://www.focusillusion.com/Instructions/ | archive-url = https://web.archive.org/web/20061023020433/http://www.focusillusion.com/Instructions/ | archive-date = 23 October 2006 | title = Instructions on how to view stereograms such as magic eye | work = FocusIllusion.com }}</ref>

Monocular diplopia may be induced in many individuals, even those with normal eyesight, with simple defocusing experiments involving fine, high-contrast lines.<ref name=Archer />