micropsia


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Related to micropsia: teleopsia

micropsia

 [mi-krop´se-ah]
a disorder of visual perception in which objects appear smaller than their actual size.

mi·crop·si·a

(mī-krop'sē-ă),
Perception of objects as smaller than they are.
[micro- + G. opsis, sight]

micropsia

The visual perception that objects are smaller than they actually are, which may be due to:
(1) Optical distortion caused by lenses, corneal swelling, retinal oedema, macular degeneration, central serous chorioretinopathy and other ocular conditions;
(2) Neurologic disorders, such traumatic brain injury, epilepsy and migraines;
(3) Drugs (either legal or illicit, including hallucinogens); or
(4) Psychological factors (e.g., Alice in Wonderland syndrome).

mi·crop·si·a

, micropsy (mī-krop'sē-ă, mīkrop-sē)
Perception of objects as smaller than they are.
[micro- + G. opsis, sight]

micropsia

Perception of objects as much smaller than they in fact are. This may be caused by an abnormal separation of the cones of the centre of the retina (so that widely-spaced points on the image are interpreted by the brain as being closer together) or may be a hallucination from drugs or disorders of brain function.

micropsia

Anomaly of visual perception in which objects appear smaller than they actually are. It may be due to a retinal disease in which the visual cells are spread apart, or to paresis of accommodation or to uncorrected presbyopia, or to the recent wear of either base-out prisms or a correction for myopia, etc. See dysmegalopsia; macropsia; metamorphopsia.
References in periodicals archive ?
Lerner and Lev-Ran described in a case report a 26-year-old patient who during an LSD intoxication presented with episodes of visual illusions in the form of macropsia, micropsia, pelopsia, and teleopsia.
A study conducted on 3224 Japanese adolescents, aged 13 to 18 years, demonstrated that the occurrence of micropsia and macropsia was 6.5% in boys and 7.3% in girls, suggesting that the visual illusions of AIWS may be not so rare in general population [10].
The clinical manifestation of an ERM can be completely asymptomatic or profoundly symptomatic with metamorphopsia, micropsia or macropsia, decreased visual acuity (VA), and loss of central vision.
Los mas caracteristicos son los que afectan a la percepcion visual, principalmente a la forma, tamano y situacion espacial de los objetos (metam orfopsia, macropsia, micropsia y teleopsia); macro y microsomatognosia si se refieren a la imagen corporal.
Micropsia, perceiving objects as smaller than their original size, can occur due to cerebrovascular disease, (36) psychogenic conditions or in foveal diseases wherein the symptom is unilateral.
Patients typically present with unilateral metamorphopsia, reduced visual acuity, a positive scotoma and micropsia. The onset of visual symptoms usually occurs during the third trimester but it can also develop during the first and second trimesters.
The authors found that certain phenomena--such as increased intensity of colors, increased vividness of objects, macropsia, micropsia, and transient paranoia--were specific to the cocaine-induced psychotic state.
This perceptual minification, also known as accommodative micropsia, was first reported by Wheatstone in 1852 (as cited in Smith, Meehan, & Day, 1992) and may be of much greater practical importance today because of the growing use of virtual image displays.
For example, metamorphopsia or micropsia associated with CSC can greatly interfere with driving or with work when an occupation requires delicate procedures.
Symptoms include defective vision positive ascotomas, metamorphopsia, micropsia and vertical diplopia due to tractional detachment of macula.
It is not uncommon, however, for patients with macular oedema to complain of micropsia. This occurs because the macular oedema effectively spreads the photoreceptors further apart, and the image is hence seen as smaller.
The perceptual symptoms (objects perceived to be smaller and farther away) could be related to accommodative or convergence micropsia, in which objects appear either to shrink or to recede when accommodation or convergence increases while retinal image size remains constant (McCready, 1965; Ono, Muter, and Mitson, 1974).