strabismus


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strabismus

(strəbĭz`məs), inability of the eyes to focus together because of an imbalance in the muscles that control eyeeye,
organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of eye are the simple eye, found in many invertebrates, and the compound eye, found in insects and many other
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 movement; also called squint. It is a consequence of weakness or uneven development of one or more of the six small muscles that surround the eye. One or both eyes may be affected. Horizontal strabismus is caused when the eyes do not move together laterally; this condition is known as cross-eye if the eye turns inward or walleye if the eye turns outward. Vertical strabismus results when the eye rolls upward or downward in its socket. There is also torsional strabismus in which the eyes do not rotate together about their optical axes. Strabismus is usually present at birth and becomes apparent early in infancy, but it may also result from illness or injury. Because the condition results in perception of a double image, there is a tendency to use only one eye. It is important that treatment be started as soon as possible to prevent loss of sight in the unused eye. Corrective therapy includes exercise that strengthens eye muscles and prescription of corrective lenses. Sometimes a patch is placed alternately on each eye so that neither is allowed to become completely unused. If necessary, the eye muscles may be shortened or lengthened surgically.
The Columbia Electronic Encyclopedia™ Copyright © 2013, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Strabismus

 

deviation of the visual axis of one of the eyes from the common point of fixation, leading to a loss of binocular vision. Two types are distinguished: concomitant and paralytic strabismus.

Concomitant strabismus, in which the deviating eye always follows the movement of the other eye and the angle of divergence of their visual axes remains constant, is observed predominantly in children (up to 2 percent). Its causes have not been conclusively elucidated. Strabismus may be accommodative, owing to anomalies of refraction and disturbances of eye accommodation, or nonaccommodative. Accommodative strabismus disappears upon administration of drops of atropine in the eye and use of corrective lenses: nonaccommodative strabismus is distinguished by extreme persistence. Strabismus may be constant or periodic, unilateral (when only one eye deviates) or alternating, and convergent (when the deviating eye moves toward the nose) or divergent (when the deviating eye moves toward the temple); the eye may simultaneously deviate upward or downward as well.

In approximately half the cases of concomitant strabismus some decrease in acuity of vision is noted in the deviating eye. The treatment of nonaccommodative strabismus is manifold, employing both various exercises for the eyes on special instruments (synoptophores, amblyoscopes) and operations directed toward weakening the stronger eye muscle or strengthening its antagonist.

Paralytic strabismus originates with paralysis of the oculomotor muscles as a result of disease of the central nervous system (infection, hemorrhage). It is characterized by limited mobility of the paralyzed eye, double images, and a different deflection angle of either eye. Treatment is directed at the disease causing the strabismus; sometimes vision can be restored by special operations on the eye muscles.

REFERENCE

Mnogotomnoe rukovodstvo po glaznym bolezniam, vol. 3, book 1. Moscow, 1962. Pages 237–355.

M. L. KRASNOV

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

strabismus

[strə′biz·məs]
(medicine)
Incoordinate action of the extrinsic ocular muscles resulting in failure of the visual axes to meet at the desired objective point. Also known as cast; heterotropia; squint.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

strabismus

abnormal alignment of one or both eyes, characterized by a turning inwards or outwards from the nose thus preventing parallel vision: caused by paralysis of an eye muscle, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
It has been shown that these therapies can decrease proptosis and significantly improve eye movements, strabismus and diplopia (Chavis 2002, Kauppinen-Makelin et al 2002, Meyer 2006, Modjtahedi et al 2006, Schotthoefer & Wallace 2007, Kuryan et al 2008).
Phase I of the study determined the sensitivity and specificity of several screening tests (and certain combinations of these tests) for detecting 1 or more of the 3 major childhood vision problems: amblyopia, strabismus, and/or significant refractive error in 2500 Head Start preschoolers.
Eye screening during childhood is important to prevent amblyopia secondary to refractive error and strabismus. Legislative decree no: 633 issued in 2011 stated that the family physician is responsible for the overall health of school-age children and must provide diagnostic and therapeutic services for the health problems of school-age children.
In adulthood, presence of strabismus may lead to psychological problems such as poor self-esteem, depression, poor interpersonal relationship and poor job opportunities because of cosmetically undesirable appearance.
Strabismus is a common vision disorder where one of the eyes looks inward, outward, up or down when the other eyes is focused on an object.
Kelly, Ph.D., from the Retina Foundation of the Southwest in Dallas, and colleagues assessed multiple-choice answer form completion time, an academic-related fine motor outcome, in 65 children (mean grade completed, 3.42) with amblyopia and strabismus and 20 control children with normal visual acuity and stereoacuity and no history of vision disorders.
The center sub-specializes in treating Cornea and External Diseases, Cataract and Refractive Surgery, Glaucoma, Low Vision and Rehabilitation, Neuro-Ophthalmology, Plastics, Lacrimals, and Orbit, Pediatric Ophthalmology and Strabismus, Medical and Surgical Retina, as well as Uveitis and Ocular Immunology.
But very little research on the eye-tracking technique for strabismus diagnosis has been reported.
A previously healthy four-year-old girl was presented to our emergency room with complaints of binocular horizontal diplopia of sudden onset and strabismus. Ophthalmological examination revealed an esotropia of the left eye in primary position, with marked abduction deficit, no palpebral fissure changes, and a vicious position of the head (left head turn).
Recently, a study regarding a wide number of IXT patients found no strong associations between stereopsis, amount of strabismus, and control of the deviation [4].
Strabismus is a common ocular disorder occurring at all ages, with an estimated prevalence of 2-5% in the general population [1-4].