1. In psychiatry, a defense mechanism that helps to repress or disguise unacceptable thoughts. 2. In dental impressions, the permanent deformation of the impression material after the registration of an imprint. 3. A twisting out of normal shape or form. 4. In ophthalmology, unequal magnification over a field of view. [L. distortio, fr. dis-torqueo, to wrench apart]
- barrel d. irregular image produced when peripheral magnification is greater than axial magnification. See Petzval surface.
- parataxic d. an attitude toward another person based on a distorted evaluation, usually because of too close an identification of that person with emotionally significant figures in the patient's past life.
- pincushion d. irregular image produced when axial magnification is greater than peripheral magnification. See Petzval surface.

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dis·tor·tion dis-'tȯr-shən n
1) the censorship of unacceptable unconscious impulses so that they are unrecognizable to the ego in the manifest content of a dream
2) a lack of correspondence of size or intensity in an image resulting from defects in an optical system

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dis·tor·tion (dis-torґshən) [dis-1 + torsio a twisting] 1. the state of being twisted out of a natural or normal shape or position. 2. in psychiatry, the process of altering or disguising unconscious ideas or impulses so that they become acceptable to the conscious mind. 3. in optics or radiology, deviation of an image from the true outline or shape of an object or structure.

Medical dictionary. 2011.