scotoma
   Also known as negative scotoma. The term scotoma comes from the Greek noun skotos (darkness). It is used to denote an area or island of loss or impairment of vision, surrounded by a field of normal or relatively well-preserved vision. In accordance with the degree of loss of vision, scotomata may be divided into relative and absolute scotomata. The group of relative scotomata is subdivided into shallow and deep scotomata. In accordance with their localization within the field of vision, scotomata are commonly divided into central and peripheral (or paracentral) sco-tomata. When central scotomata extend towards the area of the blind spot, they are referred to as centro-cecal scotomata. When central scotomata have a ring shape, leaving both central vision and peripheral vision intact, they are referred to as peri-central scotomata. When peripheral scotomata appear as an extension of the blind spot, they are referred to as Seidel's scotomata. When peripheral scotomata have a ring shape, they are referred to as annular scotomata or ring scotomata. For cases of * achromatopsia that confine themselves to an island-shaped region of the visual field, the term * colour scotoma is used. Migraine attacks are often preceded by a * scintillating scotoma, which typically takes the form of a ball of light within the central field of vision, developing into a shimmering arc of white or coloured lights. This arc may go on to assume the shape of a * fortification spectrum. The retina's * blind spot is sometimes referred to as a physiological scotoma.
   References
   Lauritzen, M. (1994). Pathophysiology of the migraine aura: The spreading depression theory. Brain, 117, 199-210.
   Sacks, O. (1992). Migraine. Revisedandexpanded. New York, NY: Vintage Books.

Dictionary of Hallucinations. . 2010.

Look at other dictionaries:

  • scotoma — (pl. scotomata), 1540s, from L.L. scotoma, from Gk. skotoma “dizziness,” from skotoun “to darken,” from skotos “darkness” (see SHADE (Cf. shade)) …   Etymology dictionary

  • Scotoma — Sco*to ma, n. [L.] (Med.) Scotomy. [1913 Webster] …   The Collaborative International Dictionary of English

  • scotoma — [skə tō′mə] n. pl. scotomata [skə tō′mə tə] or scotomas [ModL < LL, dimness of vision < Gr skotōma < skotos, darkness (see SHADE) + OMA] a dark area or gap in the visual field scotomatous [skətäm′ə təs] adj …   English World dictionary

  • Scotoma — Infobox Disease Name = PAGENAME Caption = DiseasesDB = ICD10 = ICD10|H|53|4|h|53, ICD10|H|53|1|h|53 ICD9 = ICD9|368.4, ICD9|368.12 ICDO = OMIM = MedlinePlus = eMedicineSubj = eMedicineTopic = MeshID = D012607 A scotoma (Greek: darkness ; plural:… …   Wikipedia

  • scotoma — 1. An isolated area of varying size and shape, within the visual field, in which vision is absent or depressed. 2. A blind spot in psychological awareness. [G. skotoma, vertigo, fr. skotos, darkness] absolute s. a s. in which there is no… …   Medical dictionary

  • scotoma — sco·tò·ma s.m. TS med. riduzione circoscritta della sensibilità luminosa nel campo visivo, dovuta a una lesione di un punto qualunque delle vie ottiche, dalla retina all area visiva corticale {{line}} {{/line}} DATA: av. 1749. ETIMO: dal gr.… …   Dizionario italiano

  • scotoma — n.; pl. scotomata a small area of abnormally less sensitive or absent vision in the visual field, surrounded by normal sight. All people have a blind spot in the visual field of each eye due to the small area inside the eye occupied by the optic… …   The new mediacal dictionary

  • scotoma — noun (plural mas or scotomata) Etymology: New Latin, from Medieval Latin, dimness of vision, from Greek skotōmat , skotōma, from skotoun to darken, from skotos Date: 1875 a spot in the visual field in which vision is absent or deficient …   New Collegiate Dictionary

  • Scotoma — Klassifikation nach ICD 10 H53.4 Gesichtsfelddefekte H53.1 Subjektive Sehstörungen Flimmerskotom …   Deutsch Wikipedia

  • scotoma — scotomatous /skoh tom euh teuhs/, adj. /skoh toh meuh/, n., pl. scotomas, scotomata / meuh teuh/. Pathol. loss of vision in a part of the visual field; blind spot. [1535 45; < LL < Gk skótoma dizziness. See SCOTO , OMA] * * * …   Universalium

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