Editing Diplopia (section)

=== Monocular ===
Diplopia can also occur when viewing with only one eye; this is called monocular diplopia, or where the patient perceives more than two images, monocular polyopia. While serious causes rarely may be behind monocular diplopia symptoms, this is much less often the case than with binocular diplopia.<ref name=Karmel /> The differential diagnosis of multiple image perception includes the consideration of such conditions as corneal surface [[keratoconus]], [[subluxation]] of the lens, a structural defect within the eye, a lesion in the anterior [[visual cortex]], or nonorganic conditions, but diffraction-based (rather than geometrical) optical models have shown that common optical conditions, especially [[astigmatism]], can also produce this symptom.<ref name=Archer>{{Citation | journal= Trans Am Ophthalmol Soc. | date=December 2007|volume= 105 |pages= 252–271 |author=Steven M. Archer, MD |pmc= 2258122 |title=Monocular Diplopia Due To Spherocylindrical Refractive Errors |pmid=18427616}}</ref>