请输入您要查询的英文单词：

　

单词 strabismus
释义

strabismus


stra·bis·mus

S0788000 (strə-bĭz′məs)n. A visual defect in which one eye cannot focus with the other on an object because of imbalance of the eye muscles. Also called squint.
[New Latin, from Greek strabismos, condition of squinting, from strabizein, to squint, from strabos, squinting; see streb(h)- in Indo-European roots.]
stra·bis′mal (-məl), stra·bis′mic (-mĭk) adj.

strabismus

(strəˈbɪzməs) or

strabism

n (Pathology) 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. Also called: squint [C17: via New Latin from Greek strabismos, from strabizein to squint, from strabos cross-eyed] straˈbismal, straˈbismic, straˈbismical adj

stra•bis•mus

(strəˈbɪz məs)
n. a deviation from normal orientation of one or both eyes so that both cannot be directed at the same object at the same time; squint; crossed eyes. [1675–85; < New Latin < Greek strabismós=strab(ós) squinting + -ismos -ism] stra•bis′mic, adj.

strabismus


(squint) Condition in which one eye does not look straight,” but turns in (convergent) or out (divergent). It is caused by a lack of balance between the muscles that control the eyes or a failure of the nervous system to cope with the effects of overfocusing the eyes.
Thesaurus
Noun1.strabismus - abnormal alignment of one or both eyesstrabismus - abnormal alignment of one or both eyessquintabnormalcy, abnormality - an abnormal physical condition resulting from defective genes or developmental deficienciesconvergent strabismus, crossed eye, cross-eye, esotropia - strabismus in which one or both eyes turn inward toward the nosedivergent strabismus, exotropia, walleye - strabismus in which one or both eyes are directed outward

strabismus

nounThe condition of not having the visual axes parallel:cross-eye, squint.
Translations
στραβισμόςstrabisme

strabismus


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
..... Click the link for more information.  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.

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

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.

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.

strabismus


Strabismus

 

Definition

Strabismus is a condition in which the eyes do not point in the same direction. It can also be referred to as a tropia or squint.

Description

Strabismus occurs in 2-5% of all children. About half are born with the condition, which causes one or both eyes to turn:
  • inward (esotropia or "crossed eyes")
  • outward (exotropia or "wall eyes")
  • upward (hypertropia)
  • downward (hypotropia)
Strabismus is equally common in boys and girls. It sometimes runs in families.

Types of strabismus

Esotropia is the most common type of strabismus in infants. Accommodative esotropia develops in children under age two who cross their eyes when focusing on objects nearby. This usually occurs in children who are moderately to highly farsighted (hyperopic).Another common form of strabismus, exotropia, may only be noticeable when a child looks at far-away objects, daydreams, or is tired or sick.Sometimes the eye turn is always in the same eye; however sometimes the turn alternates from one eye to the other'.Most children with strabismus have comitant strabismus. No matter where they look, the degree of deviation does not change. In incomitant strabismus, the amount of misalignment depends upon which direction the eyes are pointed.

False strabismus (pseudostrabismus)

A child may appear to have a turned eye, however this appearance may actually be due to:
  • extra skin that covers the inner corner of the eye
  • a broad, flat nose
  • eyes set unusually close together or far apart
This condition, false strabismus, usually disappears as the child's face grows. An eye doctor needs to determine whether the eyeturn is true or pseudostrabismus.With normal vision, both eyes send the brain the same message. This binocular fixation (both eyes looking directly at the same object) is necessary to see three-dimensionally and to aid in depth perception. When an eye is misaligned, the brain receives two different images. Young children learn to ignore distorted messages from a misaligned eye, but adults with strabismus often develop double vision (diplopia).A baby's eyes should be straight and parallel by three or four months of age. A child who develops strabismus after the age of eight or nine years is said to have adult-onset strabismus.

Causes and symptoms

Strabismus can be caused by a defect in muscles or the part of the brain that controls eye movement. It is especially common in children who have:
  • brain tumors
  • cerebral palsy
  • Down syndrome
  • hydrocephalus
  • other disorders that affect the brain
Diseases that cause partial or total blindness can cause strabismus. So can extreme farsightedness, cataracts, eye injury, or having much better vision in one eye than the other.In adults, strabismus is usually caused by:
  • diabetes
  • head trauma
  • stroke
  • brain tumor
  • other diseases affecting nerves that control eye muscles
The most obvious symptom of strabismus is an eye that isn't always straight. The deviation can vary from day to day or during the day. People who have strabismus often squint in bright sunlight or tilt their heads to focus their eyes.

Diagnosis

Every baby's eyes should be examined by the age of six months. A baby whose eyes have not straightened by the age of four months should be examined to rule out serious disease.A pediatrician, family doctor, ophthalmologist, or optometrist licensed to use diagnostic drugs uses drops that dilate the pupils and temporarily paralyze eye-focusing muscles to evaluate visual status and ocular health. Early diagnosis is important. Some eye turns may be a result of a tumor. Untreated strabismus can damage vision in the unused eye and possibly result in lazy eye (amblyopia).

Treatment

Preserving or restoring vision and improving appearance may involve one or more of the following:
  • glasses to aid in focusing and straighten the eye(s)
  • patching to force infants and young children to use and straighten the weaker eye
  • eye drops or ointments as a substitute for patching or glasses, or to make glasses more effective
  • surgery to tighten, relax, or reposition eye muscles
  • medication injected into an overactive eye muscle to allow the opposite muscle to straighten the eye
  • vision training (also called eye exercises)

Prognosis

Early consistent treatment usually improves vision and appearance. The most satisfactory results are achieved if the condition is corrected before the age of seven years old.

Resources

Organizations

American Academy of Ophthalmology. 655 Beach Street, P.O. Box 7424, San Francisco, CA 94120-7424. http://www.eyenet.org.American Academy of Pediatric Ophthalmology and Strabismus (AAPOS). 〈http://med-aapos.bu.edu〉.American Optometric Association. 243 North Lindbergh Blvd., St. Louis, MO 63141. (314) 991-4100. http://www.aoanet.org.

strabismus

 [strah-biz´mus] deviation of the eye that the patient cannot overcome; the visual axes assume a position relative to each other different from that required by the physiological conditions. Called also squint. adj., adj strabis´mic. The various forms of strabismus are spoken of as tropias, their direction being indicated by the appropriate prefix, as cyclotropia, esotropia, exotropia, hypertropia, and hypotropia.
During the first 3 to 6 months of life, the eyes of infants tend to waver and turn either inward or outward independently of one another; this usually corrects itself. If it persists, or if the eyes are continually crossed in the same way, even if the child is less than 6 months old, it may be a sign of strabismus. Children do not outgrow strabismus. In an older child, a tendency to tilt the head when reading, or to close or rub one eye, may indicate strabismus.
Strabismus almost always appears at an early age. If not corrected, the condition may impair vision in the nonfocusing eye, as well as marring the child's appearance. In the great majority of cases the eyes can be straightened by proper medical treatment at any age, but vision of the malfunctioning eye may remain impaired. If treated early enough, preferably before 6 years, normal vision can usually be restored in the affected eye.Cause. Strabismus may result from several factors, including a blow on the head, disease, or heredity. Many cases are caused by a malfunction of the muscles that move the eyes. This causes the eyes to focus differently, sending different images to the brain. As the child grows, he or she learns to ignore the image from one eye with the result that it fails to grow as strong as the eye on which he or she is depending.Treatment. Treatment for strabismus varies with the individual case. A patch may be placed over the child's stronger eye for a period, forcing use of the weaker eye and thus restoring its strength as far as possible, instead of letting it grow worse from lack of use. Eyeglasses or special eye exercises may correct the condition. In some cases, a relatively simple surgical operation on the eye muscles may be necessary. Since these muscles are outside the eye itself, there is no danger to the vision.comitant strabismus (concomitant strabismus) that in which the angle of deviation of the visual axis of the squinting eye is always the same in relation to the other eye, no matter what the direction of the gaze; due to faulty insertion of the eye muscles.convergent strabismus esotropia.divergent strabismus exotropia.noncomitant strabismus (nonconcomitant strabismus) that in which the amount of deviation of the squinting eye varies according to the direction in which the eyes are turned.vertical strabismus that in which the visual axis of the squinting eye deviates in the vertical plane; see hypertropia and hypotropia.

stra·bis·mus

(stra-biz'mŭs), [MIM*185100] A manifest lack of parallelism of the visual axes of the eyes. Synonym(s): crossed eyes, heterotropia, heterotropy, squint (1) [Mod. L., fr. G. strabismos, a squinting]

strabismus

(strə-bĭz′məs)n. A visual defect in which one eye cannot focus with the other on an object because of imbalance of the eye muscles. Also called squint.
stra·bis′mal (-məl), stra·bis′mic (-mĭk) adj.

strabismus

Nonparallel positioning or movement of the eyes—usually of the vertical axis—due to decreased binocular muscle coordination with loss of stereoscopic vision and inability to focus simultaneously on a single point.
 
Aetiology
Extraocular muscle defects, neurotoxins, blindness, mechanical defects, unilateral vision obstruction in childhood, various brain disorders or systemic diseases, amblyopia, paralytic shellfish poisoning, botulism, haemangioma near eye, Guillain-Barré syndrome, Apert syndrome, Noonan syndrome, Prader-Willi syndrome, trisomy 18, congenital rubella, incontinentia pigmenti, cerebral palsy, Laurence-Moon-Biedl syndrome, pseudohyperparathyroidism.

strabismus

Crossed eyes; exotropia, walleye Ophthalmology Nonparallel position or movement of eyes, due to ↓ muscle coordination between eyes, with loss of stereoscopic vision and inability to focus simultaneously on a single point Etiology Extraocular muscle defects, neurotoxins, blindness, mechanical defects, unilateral vision obstruction in childhood, various brain disorders or systemic diseases, amblyopia, paralytic shellfish poisoning, botulism, hemangioma near eye, Guillain-Barre´ syndrome, Apert syndrome, Noonan syndrome, Prader-Willi syndrome, trisomy 18, congenital rubella, incontinentia pigmenti, cerebral palsy, Laurence-Moon-Biedl syndrome, pseudohyperparathyroidism. See Farsightedness, Myopia.

stra·bis·mus

(stră-biz'mŭs) A manifest lack of parallelism of the visual axes of the eyes.
Synonym(s): crossed eyes, cross-eye, heterotropia, heterotropy, squint (1) . [Mod. L., fr. G. strabismos, a squinting]

strabismus

Squint. The condition in which only one eye is aligned on the object of interest. The other eye may be directed too far inward (convergent strabismus), too far outward (divergent squint), or upward or downward (vertical squint). Squint in childhood, or any squint of recent onset, requires urgent treatment. Untreated childhood squint often leads to AMBLYOPIA. New squints in adults usually imply a disorder of the nervous system.

strabismus 

The condition in which the lines of sight of the two eyes are not directed towards the same fixation point when the subject is actively fixating an object. Thus the image of the fixation point is not formed on the fovea of the deviated eye and there may be diplopia, although in most cases the diplopic image is suppressed and vision is essentially monocular. The prevalence of concomitant strabismus in children is 2%-5% and is far more common than paretic strabismus. Management depends on the type of strabismus. However, in all cases the refractive errors must be accurately corrected. If the deviation still prevails, orthoptics and, sometimes, pharmacological (e.g. miotics in accommodative esotropia) treatment is attempted but in many cases surgery is necessary (except where accommodation is faulty or when the deviation is small), usually followed by some orthoptics treatment aimed at developing fusion and stereopsis. Syn. heterotropia; squint (this term is commonly used by the general public); tropia. See angle of anomaly; angle of strabismus; botulinum toxin; chemodenervation; deviating eye; fixating eye; hypertropia; Bruckner's method; Hirschberg's method; Javal's method; Krimsky's method; microtropia; phi movement; zero point; past- pointing; abnormal retinal correspondence; suppression; Apert's syndrome; Brown's superior oblique tendon sheath syndrome; Crouzon's syndrome; Duane's syndrome; Marfan's syndrome; cover test; three-step test; theories of strabismus.
accommodative strabismus Convergent strabismus resulting from abnormal demand on accommodation due to an uncorrected hyperopia accompanied by excessive convergence and insufficient relative fusional divergence. The AC/A ratio (accommodative convergence to accommodation) is normal but the child has high hyperopia (refractive accommodative esotropia). It may also occur in cases in which the AC/A ratio is high and accommodation is accompanied by excessive convergence in a child with a very small amount of hyperopia (non-refractive accommodative esotropia). Accommodative strabismus is usually an acquired deviation first presenting in the first decade of life. Children do not usually notice diplopia, but instead develop suppression and later amblyopia. Management consists of full hyperopic correction and amblyopia treatment. Syn. accommodative esotropia. See cycloplegic refraction; acquired non-accommodative strabismus.
acquired strabismus An abnormal alignment of the visual axes that occurs after the age of six months.
acquired non-accommodative strabismus Convergent strabismus that presents after normal ocular alignment has been established and is not related to a subject's accommodative effort. Treatment is usually surgical. Syn. acquired non-accommodative esotropia.
alternating strabismus Strabismus in which either eye may deviate. See unilateral strabismus.
angle of strabismus See angle of deviation.
apparent strabismus Condition simulating the appearance of strabismus. It may be due to epicanthus, to an abnormally large angle lambda (or kappa), or to the breadth of the nose, etc. It can be distinguished from a real strabismus by noting that the corneal light reflexes are centrally located in relation to the pupils, or by means of the cover test. Syn. pseudostrabismus.
comitant strabismus See concomitant strabismus.
concomitant strabismus Strabismus in which the angle of deviation remains the same whichever eye is fixating and in whichever direction the eyes are looking. Syn. comitant strabismus. See concomitance; incomitant strabismus.
congenital strabismus See infantile strabismus.
consecutive strabismus A deviation of the eye in the opposite direction to what it was previously. This condition may follow surgery although it may occur spontaneously. There are two types: consecutive exotropia in a patient who previously had esotropia or esophoria and consecutive esotropia in a patient who previously had exotropia or exophoria. Syn. postoperative over-correction. See divergent strabismus.
convergent strabismus Strabismus in which the deviating eye turns inward. This is the most common type of strabismus in children. The principal categories are accommodative strabismus and non-accommodative strabismus (Fig. S15). Syn. crossed eyes (colloquial); esotropia (SOT, ET, esoT). See A pattern; V pattern; Swann's syndrome; prism adaptation test.
cyclic strabismus A very rare and unusual form of strabismus occurring on a 48-hour rhythm in which a 24-hour period of normal binocular vision is followed by 24 hours of manifest heterotropia. The condition, which may have started in early infancy, only becomes apparent during early childhood. With time, cyclic heterotropia tends to become constant. Syn. cyclic heterotropia.
deorsumvergens strabismus See hypertropia.
divergent strabismus Strabismus in which the deviating eye turns outward (Fig. S15). Syn. exotropia (XOT; XT; exoT). The principal categories are constant exotropia and intermittent exotropia. Constant exotropia may be congenital which is often associated with an underlying neurological anomaly or basic which appears after six months of age with equal exotropia for near and distance vision. Both types are usually treated surgically. Consecutive strabismus can also be a constant exotropia. Intermittent exotropia is the most common form of exotropia. It begins as an exophoria and breaks down to exotropia presenting in children between two and five years of age. It is characterized by worse exotropia at near (convergence excess) or worse exotropia at distance (divergence excess). Treatment includes spectacle correction, orthoptic exercises or surgery. See A pattern; V pattern.
strabismus fixus A rare, congenital condition in which one or both eyes are firmly fixed in a position of extreme adduction or abduction, although the most common position is adduction (esotropia). It is due to an anatomical anomaly (e.g. anomalous insertion of the medial or lateral rectus muscle), or muscle fibrosis (e.g. of the two medial recti muscle in esotropia). Voluntary movements of duction and version, as well as passive movements as in the forced duction test, are either absent or insignificant. See forced duction test.
incomitant strabismus Strabismus in which the angle of deviation varies with the direction of gaze and with the eye used for fixation. It may be congenital or acquired. The congenital type is due to some developmental anomaly of one or more of the extraocular muscles or of the neural component that serves them. The acquired type may be due to head injury, disease of the oculomotor system, or systemic disease (e.g. multiple sclerosis, myasthenia gravis, thyroid eye disease, aneurysms). The main symptom of incomitant strabismus is diplopia and it suddenly appears in the acquired type. Abnormal head posture and past-pointing may be present. The affected muscle(s) may be detected by the motility test. Treatment is aimed first at the primary cause but, in general, this type of strabismus does not respond well to orthoptic procedures. In large deviation, surgery is usually the only remedy. Syn. nonconcomitant strabismus. See abnormal head posture; incomitance; pointing past-; Hess screen; paralytic strabismus; motility test.
infantile strabismus Strabismus which becomes manifest within the first year of life. It is almost always esotropic in nature: exotropia, which is very rare, is usually associated with some neurological condition. Infantile strabismus is characterized by a large angle of squint, hyperopia, alternate fixation that may become unilateral if amblyopia develops, and nystagmus. Management is essentially surgical after correction of the refractive error. A complication following surgery may be dissociated vertical deviation. Syn. congenital strabismus; infantile esotropia syndrome. See cross-fixation.
intermittent strabismus Strabismus that is not present at all times.
monocular strabismus See unilateral strabismus.
non-accommodative strabismus Convergent strabismus not due to abnormal demands on accommodation. There are several types: infantile strabismus, acquired non-accommodative strabismus, basic esotropia (no significant hyperopia and the deviation is equal for near and distance), microtropia, convergence excess (esotropia for near vision but not for distance), divergence insufficiency (esotropia for distance vision but not for near), consecutive strabismus, sensory strabismus and cyclic esotropia (periodic manifestation of esotropia as for example on alternate days). Treatment of associated amblyopia and correction of hyperopia are often followed by surgery.
nonconcomitant strabismus See incomitant strabismus.
paralytic strabismus Strabismus due to a paralysis of the extraocular muscles. It usually gives rise to incomitance. The paralysis is usually due to a disorder of the third, fourth or sixth cranial nerve. Diplopia is noticed if the paralysis is recent and it is usually accompanied by an abnormal head posture. In most cases there is not a complete loss of action of a muscle but a partial loss and the condition is referred to as paretic strabismus, whether it is congenital or acquired. Orthoptic treatment is very limited in these cases and is not normally appropriate if the deviation was caused by injury or a recent disease. Cosmetic surgery is often necessary. See abnormal head posture; incomitance; paralysis of the fourth nerve; paralysis of the sixth nerve; paralysis of the third nerve; motility test.
periodic strabismus Strabismus in which the deviation occurs only at certain distances or in certain directions of fixation. Syn. relative strabismus.
relative strabismus See periodic strabismus.
secondary s . Strabismus resulting from a sensory deficit, surgical intervention, tumour, trauma or stroke. See consecutive strabismus; sensory strabismus.
sensory strabismus Strabismus caused by a unilateral reduction in visual acuity which disrupts binocular vision, such as unilateral cataract, optic atrophy, uncorrected anisometropia or other unilateral visual impairments.
small angle strabismus See microtropia.
strabismus surgery  See myectomy; myotomy; Faden procedure; tuck procedure; recession; resection; transposition.
sursumvergens strabismus See hypertropia.
unilateral strabismus Strabismus in which the deviating eye is always the same, as distinguished from alternating strabismus. Syn. monocular strabismus.enlarge picture" >Fig. S15 A, left convergent strabismus; B, left divergent strabismus; C, left hypertropia; D, left hypotropiaenlarge pictureFig. S15 A, left convergent strabismus; B, left divergent strabismus; C, left hypertropia; D, left hypotropia

stra·bis·mus

(stră-biz'mŭs) [MIM*185100] A manifest lack of parallelism of the visual axes of the eyes.
Synonym(s): crossed eyes, heterotropia, squint (1) . [Mod. L., fr. G. strabismos, a squinting]
AcronymsSeeSTBM

strabismus


  • noun

Synonyms for strabismus

noun the condition of not having the visual axes parallel

Synonyms

  • cross-eye
  • squint

Synonyms for strabismus

noun abnormal alignment of one or both eyes

Synonyms

  • squint

Related Words

  • abnormalcy
  • abnormality
  • convergent strabismus
  • crossed eye
  • cross-eye
  • esotropia
  • divergent strabismus
  • exotropia
  • walleye
随便看

　

英语词典包含2567994条英英释义在线翻译词条，基本涵盖了全部常用单词的英英翻译及用法，是英语学习的有利工具。

　

Copyright © 2004-2022 Newdu.com All Rights Reserved
更新时间：2025/1/11 10:49:48