title: The entoptic view of the retinal vessels.
abstract: The first time the retinal vessels were seen in man in vivo was reported in 1819 by Purkinje as an entoptic view. This was understood to show the shadow of the vessels, an interpretation objected to in 1834 by Brewster. Müller in 1855 (Über die entoptische wahrnehmung der netzhautgefässe, insbesondere als beweismittel für die lichtperception durch die nach hinten gelegenen netzhautelemente, Stahel, Würzburg) used the phenomenon to deduce the location of the photoreceptive layer of the retina, and his conclusion is accepted as true today. Because the phenomenon has some characteristics of an afterimage, it touches on the question of what is subjective and what is objective physical reality. It was recently used clinically to measure potential visual acuity and in the diagnoses of diabetic retinopathy and macular degeneration.
authors.affiliation: Yale-New Haven Hospital, New Haven, CT, USA.
authors.forename: Harry H
authors.initials: HH
authors.lastname: Mark
mesh_terms: D049671:History, 18th Century; D049672:History, 19th Century; D049673:History, 20th Century; D049674:History, 21st Century; D006801:Humans; D009885:Ophthalmology / Q000266:history*; D012164:Retinal Diseases / Q000266:history* / Q000473:pathology / Q000503:physiopathology; D012171:Retinal Vessels / Q000473:pathology*; D014788:Vision, Entoptic
keywords: H. Müller; afterimage; angioscotometry; entoptic phenomena; photoreception Purkinje; retinal vessels; visual neuroscience