Strabismus | definition of strabismus by Medical dictionary Strabismus | definition of strabismus by Medical dictionary 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) 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 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 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 American Academy of Ophthalmology. 655 Beach Street, P.O.

Box 7424, San Francisco, CA 94120-7424. American Academy of Pediatric Ophthalmology and Strabismus (AAPOS). 〈〉. American Optometric Association. 243 North Lindbergh Blvd., St. Louis, MO 63141. (314) 991-4100. 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. 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 [Mod. L., fr. G. strabismos, a squinting] strabismus /stra·bis·mus/ (strah-biz´mus) squint; deviation of the eye which the patient cannot overcome; the visual axes assume a position relative to each other different from that required by the physiological conditions.strabis´mic concomitant strabismus that due to faulty insertion of the eye muscles, resulting in the same amount of deviation regardless of the direction of the gaze. divergent strabismus exotropia . nonconcomitant strabismus that in which the amount of deviation of the squinting eye varies according to the direction of gaze. vertical strabismus that in which the visual axis of the squinting eye deviates in the vertical plane (hypertropia or hypotropia). 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 [strəbiz′məs] Etymology: Gk, strabismos, squint an abnormal ocular condition in which the visual axes of the eyes are not directed at the same point. There are two kinds of strabismus, paralytic and nonparalytic. Paralytic strabismus results from the inability of the ocular muscles to move the eye because of neurologic deficit or muscular dysfunction. The muscle that is dysfunctional may be identified by watching as the patient attempts to move the eyes to each of the cardinal positions of gaze. If the affected eye cannot be directed to a position, the examiner infers that the associated ocular muscle is the dysfunctional one. Because this kind of strabismus may be caused by tumor, infection, or injury to the brain or the eye, an ophthalmologic examination is recommended. Nonparalytic strabismus is a defect in the position of the two eyes in relation to each other.

The condition may be inherited. The person cannot use the two eyes together but has to fixate with one or the other. The eye that looks straight at a given time is the fixing eye. Some people have alternating strabismus, using one eye and then the other; some have monocular strabismus, which affects only one eye. Visual acuity diminishes with diminished use of an eye, and suppression amblyopia may develop. Nonparalytic strabismus and suppression amblyopia are treated most successfully in early childhood. The primary treatment to prevent amblyopia consists mainly of covering the fixing eye, forcing the child to use the deviating eye. The earlier it is begun, the more rapid and effective is the treatment. The eyes might be straightened by surgery, but suppression amblyopia will not be corrected. Also called squint. See also anoopsia, esotropia , exotropia. strabismal, strabismic, strabismical, adj. Strabismus 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 [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 (str ·bizˑ·m s), n a condition wherein the two visual axes of the eyes are not aimed at a single object. In paralytic strabismus the muscles in the eyes are unable to move because of infection, tumor, or injury. In nonparalytic strabismus, there is a defect in the location of the eyes in relationship to their focal point. Also called squint. Strabismus. 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. Fig. S15 A, left convergent strabismus; B, left divergent strabismus; C, left hypertropia; D, left hypotropia stra·bis·mus [Mod. L., fr. G.

strabismos, a squinting] strabismus (strəbiz´məs), n an abnormal ocular condition in which the eyes are crossed. strabismus 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. Basic types of strabismus. By permission from Guyton R, Hall JE, Textbook of Medical Physiology, Saunders, 2000 comitant strabismus extraocular muscles are not paralyzed and the degree of deviation is the same in all directions. congenital strabismus medial strabismus is seen in Siamese cats. See convergent strabismus (below). convergent strabismus that in which the visual axes converge; esotropia, or cross-eye. A frequent finding in Siamese cats, related to an anomaly of neuronal pathways between the retina and lateral geniculate nucleus in which more neurons project contralaterally rather than ipsilaterally as in other cats. divergent strabismus that in which the visual axes diverge; called also exotropia and walleye.

inherited strabismus Strabismus: MedlinePlus Medical Encyclopedia Traumatic brain injury Vision loss from any eye disease or injury A family history of strabismus is a risk factor. Farsightedness may be a contributing factor, especially in children. Any other disease that causes vision loss may also cause strabismus. Symptoms Symptoms of strabismus may be present all the time, or may come and go. Symptoms can include: Crossed eyes Eyes that do not align in the same direction Uncoordinated eye movements (eyes do not move together) Loss of vision or depth perception It is important to note that children may never have double vision because amblyopia can develop quickly. Exams and Tests The health care provider will do a physical exam that includes a detailed examination of the eyes. Tests will be done to determine how much the eyes are out of alignment. Corneal light reflex A brain and nervous system (neurological) exam will also be done. Treatment The first step in treating strabismus in children is to prescribe glasses, if needed. Next, amblyopia or lazy eye must be treated. A patch is placed over the better eye.

This forces the weaker eye to work harder and get better vision. Your child may not like wearing a patch or eyeglasses. A patch forces the child to see through the weaker eye at first. However, it is very important to use the patch or eyeglasses as directed. Eye muscle surgery may be needed if the eyes still do not move correctly. Different muscles in the eye will be made stronger or weaker. Eye muscle repair surgery does not fix the poor vision of a lazy eye. Muscle surgery will fail if amblyopia has not been treated. A child may still have to wear glasses after surgery. Surgery is more often successful if done when the child is younger. Adults with mild strabismus that comes and goes may do well with glasses and eye muscle exercises to help keep the eyes straight. More severe forms will require surgery to straighten the eyes. If strabismus has occurred because of vision loss, the vision loss will need to be corrected before strabismus surgery can be successful. Outlook (Prognosis) After surgery, the eyes may look straight, but vision problems can remain. The child may still have reading problems in school. Adults may have a hard time driving.

Vision may affect the ability to play sports. In most cases, the problem can be corrected if identified and treated early. Permanent vision loss in one eye may occur if treatment is delayed. If amblyopia is not treated by about age 11, it is likely to be permanent. About one-third of children with strabismus will develop amblyopia. Many children will get strabismus or amblyopia again, so the child will need to be monitored closely. When to Contact a Medical Professional Strabismus should be evaluated promptly. Call your health care provider or eye doctor if your child: Appears to be cross-eyed Complains of double vision Has difficulty seeing Note: Learning and school problems can sometimes be due to a child's inability to see the blackboard or reading material. Alternative Names Crossed eyes; Esotropia; Exotropia; Hypotropia; Hypertropia; Squint; Walleye; Misalignment of the eyes Images Walleyes References Cibis GW, Ing M. Binocular vision. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed.

Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 5. Goldstein HP, Scott AB. Ocular motility. In: Tasman W, Jaeger EA, eds. Duane's Foundations of Clinical Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 2, chap 23. Parks MM. Binocular vision adaptations and maldevelopments monofixation syndrome, microstrabismus, and macrostrabismus. In: Tasman W, Jaeger EA, eds. Duane's Ophthalmology. 2013 ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2012:vol 1, chap 8. Olitsky SE, Hug D, Plummer LS, Stass-Isern M. Disorders of eye movement and alignment. In: Kliegman RM, Behrman RE, Jenson HB, Stanton BF, eds. Nelson Textbook of Pediatrics. 19th ed.

Philadelphia, PA: Elsevier Saunders; 2011:chap 615. Read More Squint | definition of squint by Medical dictionary Squint | definition of squint by Medical dictionary 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. 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 . squint 2. To suffer from strabismus. squint 1.

To look with the eyes partly closed, as in bright sunlight. 2. To be affected with strabismus. n. See strabismus . 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. squint Ophthalmology See Strabismus Vox populi The closing of orbicular muscles to examine a distant object. squint 2. To narrow the interpalpebral openings of the eyelids to block light or improve focus. squint See STRABISMUS .

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. Fig. S15 A, left convergent strabismus; B, left divergent strabismus; C, left hypertropia; D, left hypotropia stra·bis·mus Strabismus - definition of strabismus by The Free Dictionary Strabismus - definition of strabismus by The Free Dictionary (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 the Appendix of Indo-European roots.] stra·bis′mal (-məl), stra·bis′mic (-mĭk) adj. strabismus 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 (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. ThesaurusAntonymsRelated WordsSynonymsLegend: squint abnormalcy , abnormality - an abnormal physical condition resulting from defective genes or developmental deficiencies convergent strabismus , crossed eye , cross-eye , esotropia - strabismus in which one or both eyes turn inward toward the nose divergent strabismus , exotropia , walleye - strabismus in which one or both eyes are directed outward strabismus n. estrabismo, alineamiento anormal de los ojos debido a una deficiencia muscular; pop. bizquera. strabismus n estrabismo Want to thank TFD for its existence?

Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: hagioscope References in periodicals archive ? The National Institute of Ophthalmology also projected that at least 50,000 children in Central Vietnam have some type of strabismus, and about 2,500 children have ptosis. The Orbis Flying Eye Hospital Conducts Intensive Ophthalmic Training Program in Hue for the First Time Strabismus is a misalignment of the eyes due to a muscle imbalance and can be present constantly or may be intermittent. The paediatric ophthalmic examination: examination of a child's eye can be challenging and traumatic but could save the child's sight or even his life Ukraine's head ophthalmologist Sergiy Rykov informed that the new method introduced by Ukrainian doctors decreases the number of surgeries needed in case of strabismus to only one, while previously two to three operations were normally executed in order to restore binocular vision.

Ukrainian Medics Present Innovative Method to Treat Strabismus One hundred and one American Society of Anesthesiologists physical status I and II patients, aged one to 13 years, scheduled to undergo strabismus surgery under general anaesthesia were enrolled in the study. Prophylactic use of midazolam or propofol at the end of surgery may reduce the incidence of emergence agitation after sevoflurane anaesthesia I was born with a strabismus and have had to wear glasses since I was seven months old. Marion looks on the bright side of her life; The eye condition strabismus, commonly known as a squint, affects approximately one in 20 children. Here MARION SAUVEBOIS, left, talks openly about what it's like to live with the condition No confirmed reports have been made of serious toxin spread when Botox has been used at the recommended dose to treat chronic migraine, hyperhidrosis, blepharospasm, or strabismus or when Botox Cosmetic has been used at the recommended dose to treat frown lines, the agency said.

Strabismus | Article about strabismus by The Free Dictionary Strabismus | Article about strabismus by The Free Dictionary Also found in: Dictionary , Thesaurus , Medical , Acronyms , Wikipedia . strabismus (strəbĭz`məs), inability of the eyes to focus together because of an imbalance in the muscles that control eye eye, 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 Strabismus - What does strabismus stand for? The Free Dictionary Strabismus - What does strabismus stand for? The Free Dictionary Sturgill Turner Barker Moloney (Lexington, Kentucky) STBM System Test and Boot Master StBM Southern Tier Bassmasters (Little Genesee, NY) STBM STBM Seam To Be Mined Want to thank TFD for its existence? Tell a friend about us , add a link to this page, or visit the webmaster's page for free fun content . Link to this page: References in periodicals archive ? Diagnostic set for treating strabismus - optical compensators KK-42 - ensued from collaboration of several Ukrainian medical research institutions. Ukrainian Medics Present Innovative Method to Treat Strabismus A total of 101 children presenting for strabismus surgery under sevoflurane anaesthesia were included in the study.

Prophylactic use of midazolam or propofol at the end of surgery may reduce the incidence of emergence agitation after sevoflurane anaesthesia The big problem with strabismus is the terribly noticeable squint that comes with it. Strabismus (Crossed Eyes): did you really understand what your eye doctor told you? Did you really understand what your eye doctor told you? Excerpted from Taking Care of Your Eyes ï¿½ 2003-2005 by Triad Communications strabismus. (Also called crossed eyes, deviation, heterotropia, squint, tropia.) Eye misalignment or eyes that do not move normallly, caused by extraocular muscle imbalance. One fovea is not directed at the same object as the other. (From Dictionary of Eye Terminology , 4th ed, ï¿½ 2001 by Triad Communications) STRABISMUS (Crossed Eyes) An excerpt from the book Taking Care of Your Eyes , useful practical information about common and less-common eye diseases and disorders, and what you can expect - from examination through treatment, and afterward.

Strabismus (struh-BIZ-muss) is a broad medical term that refers to various misalignments (deviations) of the eye, such as "crossed eyes." For the two eyes to be properly aligned, they need to have similar vision and focusing ability, and the muscles that move them need to work together. Only then can a person have binocular vision and depth perception, meaning that the images from each eye are fused (blended) by the brain into a single image that appears three-dimensional. If one eye does not look in the same direction as the other, binocular vision cannot exist. In a young child, the deviating eye may eventually lose its ability to see clearly. This is called amblyopia, or "lazy eye." "Comitant" strabismus, the type usually seen in children, means that no matter in what direction the eyes look, the amount of misalignment (deviation) is the same. This is in contrast to "incomitant" strabismus, in which the amount of deviation is constantly changing, depending on which direction you look. Strabismus affects about two to four percent of all children (boys and girls equally) and tends to run in families.

What Causes Strabismus? Most often, there is no identifiable cause -- the child is simply born with a misalignment or develops it early in childhood. But there are also many known causes, for example: one eye that is blind or has defective vision from birth (as from a congenital cataract); one eye that is extremely nearsighted, farsighted or astigmatic, or the amount of eyeglass correction required by the two eyes is vastly different; one or more absent, injured or defective nerves to the eye muscles, causing the muscles controlled by the nerve to function improperly; damage to an area of the brain dealing with eye movement or eye muscle control; injury from trauma that damages any eye muscles or nerves; blindness from disease or injury. Intentionally crossing the eyes is never a cause of strabismus; the eyes cannot get "stuck" in a crossed position. Types of Strabismus The most common type, in which one eye turns inward (crossed eyes), is esotropia. It is also called "convergent strabismus" because the eyes converge or turn toward each other.

With exotropia (wall eyes), one eye turns out; it is also called "divergent strabismus." Less common are hypertropia (one eye turns upward) and hypotropia (one eye turns downward). In some people it is always the same eye that deviates. In others the deviation shifts from one eye to the other; this is called alternating. Alternating strabismus can be confusing to parents. You notice that one eye seems to turn, and just when you have concluded which one it is, the other eye seems to be the culprit. "Adult-onset strabismus" is any misalignment that comes on after normal binocular vision has developed (usually by the age of 8). Unlike childhood strabismus, the adult type usually creates symptoms, such as double vision (diplopia), which may be accompanied by nausea. What Is a Phoria? "Tropia" is another word for strabismus (as in esoTROPIA). "Phoria" is a related condition in which the misalignment is not apparent. It is only a tendency, and it is usually kept under control so that the eyes appear normal and work together normally.

(The misalignment can be unmasked by covering either one of the eyes.) Phorias are named in the same way as tropias: esoPHORIA (tendency for one eye to turn in), exophoria (out), hyperphoria (up), and hypophoria (down). Most phorias cause no symptoms at all. But if the phoria is large, great effort may be needed to keep the eyes aligned and working together - to avoid seeing double - and this may cause eyestrain and headache. Sometimes, when the strabismus is intermittent, the eyes stay aligned and appear straight some of the time, but lapse into strabismus at other times. These lapses occur more commonly with outward deviations than with other types. At the times when the eyes appear straight, an exophoria is present, and when one eye starts turning out, this is a frank exotropia. The tropia is more likely to occur late in the day, in the bright outdoors, or when you are ill. As the years go on, intermittent strabismus tends to become more constant and less intermittent.

Examination The eyes should be examined as soon as you even suspect that they might be crossing or wandering, no matter how small the misalignment might be. No child is too young to be seen and early care can prevent later heartache. The sooner treatment is begun, the better your child's chance for achieving normal vision in each eye and good binocular depth perception. Correction after the age of 6 or 7 is more difficult and the result less satisfactory. A complete eye examination and refraction (measurement of vision and a check for glasses) involves the use of eyedrops to dilate the pupils and temporarily paralyze the focusing mechanism. Eye movements, quality and degree of stereopsis (3-D vision), and the ability to recognize double vision will all be checked, depending on the age and cooperation of the patient. Determination of the cause may involve referral to other types of specialists. Goals of Treatment For children, your doctor will try to achieve normal appearance, good vision in each eye (with or without glasses), binocular vision, and depth perception. In adults, the goals are binocular vision (which eliminates double vision) and relief of any discomfort.

If an adult has a childhood strabismus that was never treated, it is too late to improve any amblyopia or depth perception, so the goal may be simply cosmetic -- to make the eyes appear to be properly aligned -- though sometimes treatment does enlarge the extent of side vision. Treatment Treatment may consist of eyeglasses, patching, eye coordination exercises (called orthoptics) and/or surgery on the eye muscles. Eyeglasses, with or without patching, are often tried first and can usually reduce the amount of deviation. This is especially true for accommodative esotropia, a type of strabismus in which farsightedness is a major part of the problem. (Eyeglasses can be worn by infants as young as a few months.) The glasses must usually be worn constantly, often for life. If surgery is thought necessary, it is designed to correct only the deviation that remains with the glasses on. In cases of slight or intermittent misalignment, orthoptics exercises are occasionally useful, but only in very specific circumstances. Used inappropriately, orthoptics can be wasteful and can lead to delay in starting proper treatment.

"Patching" is the main treatment for infants and young children who have poor vision (amblyopia) associated with strabismus. A patch is placed over the normal (preferred eye), to force the use of the deviant (amblyopic) eye until vision improves and equalizes. Generally, surgery is postponed until that happens. In adults, a patch over one eye is one method of eliminating any double vision. Prisms incorporated into the eyeglasses is another. Surgery consists of tightening some eye muscles and loosening others, to change their pull on the eyeball and bring the eyes into alignment. (Occasionally, a loosening effect can be accomplished without surgery by injecting a paralyzing medication, called Oculinum, directly into the muscle.) Surgery is sometimes performed on infants as young as a few months of age when there is a good chance of obtaining binocular vision. Children require a general anesthetic. Adults often prefer to have a local. During the first month or two following surgery, exercises may be designed to redevelop the ability to use both eyes together normally. Strabismus surgery is quite safe, though it does involve some risks as does any surgery and anesthesia.

If an operation is necessary in your case, your doctor will explain the risks along with the potential benefits. Many times, more than one operation is necessary to obtain good eye alignment. Glasses may also be required after surgery to obtain the best possible visual result. Prognosis The outcome of treatment is dependent on many factors, such as the type of strabismus, age of onset, and visual acuity of each eye. It often involves years of commitment and care. Most patients can obtain comfort and a highly acceptable appearance with good eye alignment; some also gain fully normal function, with coordinated use of both eyes (binocular fusion and depth perception). Each patient's potential for a good result is different. This fact must be well understood to avoid disappointment. Hypertropia | Article about hypertropia by The Free Dictionary Hypertropia | Article about hypertropia by The Free Dictionary Related to hypertropia: hyperphoria , hypotropia strabismus (strəbĭz`məs), inability of the eyes to focus together because of an imbalance in the muscles that control eye eye, 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

Question: Strabismus is more commonly known by which one-syllable word?
Answer: SQUINT