entoptic phenomenon — Also known as entoptic imagery, entoptic image, and entoptic form. All four terms are indebted to the Greek words entos (inside) and opsis (seeing). Traditionally the expression entoptic phenomenon is used to denote any member of a group of… … Dictionary of Hallucinations
Closed-eye hallucination — Closed eye hallucinations and closed eye visualizations (CEV) are a distinct class of hallucination. These types of hallucinations generally only occur when one s eyes are closed or when one is in a darkened room. They are a form of phosphene.… … Wikipedia
geometric hallucination — Also known as geometrical hallucination, geometric visual hallucination, and optogeometric illusion. All four terms can be traced to the Greek noun geometria, which means land surveying. They are used to denote a * formed visual hallucination… … Dictionary of Hallucinations
visual hallucination — Also referred to as vision. Both terms are indebted to the Latin noun visio, which means sight. They are used to denote a hallucination of sight. Historically, visual hallucinations have been divided into a multitude of types. Using their… … Dictionary of Hallucinations
simple hallucination — Also referred to as elementary hallucination. Both terms are used to denote a hallucination of the lowest degree of complexity. In the auditory modality, simple hallucinations are known as * akoasms. Common examples of akoasms are clicking… … Dictionary of Hallucinations
closed-eye hallucination — Also known as closed eye visual hallucination and closed eye visualization. All three terms are used to denote a type of *visual hallucination experienced exclusively when the eyes are closed or when there is perfect darkness around. Some… … Dictionary of Hallucinations
Visual snow — is a transitory or persisting visual symptom where people see snow or television like static in parts or the whole of their visual fields, especially against dark backgrounds. It is much like camera noise in low light conditions. The severity or… … Wikipedia
centripetal theory of hallucinatory activity — The name centripetal theory refers to an explanatory model of hallucinatory activity which is traditionally attributed to the German physiologist and zoologist Johannes Peter Müller (18011858). Conceptually, the centripetal theory constitutes… … Dictionary of Hallucinations
fiery rings of Purkinje — The eponym fiery rings of Purkinje refers to the Bohemian physiologist Johannes Evangelista Purkyne (1787 1869), who is credited with being the first to describe the concomitant phenomenon in his textbook of 1823. The phenomenon consists of… … Dictionary of Hallucinations
Optical illusion — This article is about visual perception. For the Time Requiem album, see Optical Illusion (album). An optical illusion. The square A is exactly the same shade of gray as square B. See checker shadow illusion. An optical illusion (also called a… … Wikipedia
