An optical explanation of the entoptic phenomenon of 'clouds' in posterior vitreous detachment

Serpetopoulos, CN; Korakitis, RA

dc.contributor.author	Serpetopoulos, CN	en
dc.contributor.author	Korakitis, RA	en
dc.date.accessioned	2014-03-01T01:47:07Z
dc.date.available	2014-03-01T01:47:07Z
dc.date.issued	1998	en
dc.identifier.issn	02755408	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/25151
dc.subject.other	article	en
dc.subject.other	human	en
dc.subject.other	illumination	en
dc.subject.other	priority journal	en
dc.subject.other	retina	en
dc.subject.other	visual disorder	en
dc.subject.other	vitreous opacity	en
dc.subject.other	Humans	en
dc.subject.other	Lighting	en
dc.subject.other	Optics	en
dc.subject.other	Vision	en
dc.subject.other	Vision Disorders	en
dc.subject.other	Vitreous Detachment	en
dc.title	An optical explanation of the entoptic phenomenon of 'clouds' in posterior vitreous detachment	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0275-5408(98)00018-0	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0275-5408(98)00018-0	en
heal.publicationDate	1998	en
heal.abstract	The purpose of this work is to investigate in detail the optics of the shadow cast by vitreous opacities and its effects in the perception of related entoptic phenomena. The optics of the eclipse has been used as a model. The various parameters affecting the shadow, i.e. the diameter of the opacity, its distance from the retina and the overall distance between the pupillary plane and the retina, have been taken into account in the calculations. A mathematical function has been derived and curves defining the density of the penumbra have been plotted for various distances of an opacity from the retina. An area of uniform partial illumination of the retina behind the opacity has been defined, outside of which the density of the penumbra falls rapidly. It is concluded that the sensation of 'cloud' or 'smoke' reported by the patient stems from this uniform area of penumbra behind the opacity, whose extent depends on the above mentioned parameters. Thus, the optics of the eclipse explains this entoptic phenomenon. Of course, 'clouds' can also be due to semi-transparent vitreous floaters.	en
heal.journalName	Ophthalmic and Physiological Optics	en
dc.identifier.doi	10.1016/S0275-5408(98)00018-0	en
dc.identifier.volume	18	en
dc.identifier.issue	5	en
dc.identifier.spage	446	en
dc.identifier.epage	451	en