Strabismus Prof.Dr. Emel Başar İ.Ü. Cerrahpaşa Tıp Fakültesi, Göz Hastalıkları Anabilim Dalı

StrabismusStrabismus

Prof.Dr. Emel BaşarProf.Dr. Emel Başar

İ.Ü. Cerrahpaşa Tıp Fakültesi, İ.Ü. Cerrahpaşa Tıp Fakültesi,

Göz Hastalıkları Anabilim DalıGöz Hastalıkları Anabilim Dalı

SYNONYMSSYNONYMS

SquintSquint Cross-eyed Cross-eyed Wall-eyedWall-eyed

DESCRIPTIONDESCRIPTION

Misalignment of the eyes, such that both eyes are Misalignment of the eyes, such that both eyes are not simultaneously directed at the same objectnot simultaneously directed at the same object

Esotropia Esotropia is a common type of strabismus is a common type of strabismus characterized by inward deviation of one eye characterized by inward deviation of one eye relative to the otherrelative to the other

Infantile esotropia is inward deviation of the eyes Infantile esotropia is inward deviation of the eyes noted before the patient reaches age 6 monthsnoted before the patient reaches age 6 months

Exotropia Exotropia is a common type of strabismus is a common type of strabismus characterized by outward deviation of one eyecharacterized by outward deviation of one eye

relative to the otherrelative to the other

CONCOMITANT STRABISMUSCONCOMITANT STRABISMUS

EPIDEMIOLOGYEPIDEMIOLOGY

Incidence and prevalenceIncidence and prevalence

PREVALENCEPREVALENCE One of the most prevalent ocular problems among One of the most prevalent ocular problems among

children, affecting 50 in every 1000 US citizens, or children, affecting 50 in every 1000 US citizens, or some 12 million people in a population of 245 million some 12 million people in a population of 245 million

Estimated prevalence of strabismus in the general Estimated prevalence of strabismus in the general population is 20-60/1000 population is 20-60/1000

Of this, infantile esotropia is believed to affect about Of this, infantile esotropia is believed to affect about 1 % of full-term, healthy newborns and a much 1 % of full-term, healthy newborns and a much higher percentage of newborns with perinatal higher percentage of newborns with perinatal complications due to prematurity or complications due to prematurity or hypoxic/ischemic encephalopathyhypoxic/ischemic encephalopathy

EPIDEMIOLOGYEPIDEMIOLOGYDemographicsDemographicsAGEAGE

Usually presents in patients aged 2-3 yearsUsually presents in patients aged 2-3 years By definition, infantile esotropia is seen in infants By definition, infantile esotropia is seen in infants

before age 6 monthsbefore age 6 monthsGENDERGENDER

No gender predilection exists.No gender predilection exists.RACERACE

No racial predilection exists.No racial predilection exists.GENETICSGENETICS

It is strongly believed that a genetic component It is strongly believed that a genetic component exists, but a solid basis for linkages among family exists, but a solid basis for linkages among family members is still to be establishedmembers is still to be established

Around 20-30% of children born to a strabismic Around 20-30% of children born to a strabismic parent will eventually develop strabismusparent will eventually develop strabismus

CAUSES OF STRABISMUS CAUSES OF STRABISMUS Common causesCommon causes

Exact cause of infantile esotropia remains unknownExact cause of infantile esotropia remains unknown Results from paralysis of one or more ocular Results from paralysis of one or more ocular

muscles; may be caused by a specific oculomotor muscles; may be caused by a specific oculomotor nerve lesion (nerve lesion (Paralytic StrabismusParalytic Strabismus) )

Disuse of an eye, as in cases of severe refractive Disuse of an eye, as in cases of severe refractive error or impaired vision due to disease, may also error or impaired vision due to disease, may also result in strabismus result in strabismus

Ambiyopia or lazy eye (reduced visual acuity Ambiyopia or lazy eye (reduced visual acuity caused by an abnormal visual experience early in caused by an abnormal visual experience early in life) may occur in strabismus, usually due to life) may occur in strabismus, usually due to cortical suppression of the image in the deviating cortical suppression of the image in the deviating eye to avoid confusion and diplopiaeye to avoid confusion and diplopia

CAUSES OF STRABISMUS CAUSES OF STRABISMUS

Rare causesRare causes Patients with craniofaciai syndromes, ocular Patients with craniofaciai syndromes, ocular

albinism, midline defects, and cerebral palsy albinism, midline defects, and cerebral palsy may present with congenital exotropia.may present with congenital exotropia.

CAUSES OF STRABISMUS CAUSES OF STRABISMUS

Serious causesSerious causes A specific oculomotor nerve lesion may cause A specific oculomotor nerve lesion may cause

paralysis of one or more ocular musclesparalysis of one or more ocular muscles

In children, such a nerve lesion may be caused by In children, such a nerve lesion may be caused by

cerebral palsy, Down syndrome,hydrocephalus, or cerebral palsy, Down syndrome,hydrocephalus, or

brain tumorsbrain tumors

In adults, nerve lesion may be caused by stroke, In adults, nerve lesion may be caused by stroke,

diabetes, cardiovascular disease, tumors, or traumadiabetes, cardiovascular disease, tumors, or trauma

If there is a cranial nerve lesion the strabismus it is If there is a cranial nerve lesion the strabismus it is

paralyticparalytic

CAUSES OF STRABISMUSCAUSES OF STRABISMUS

Contributory or predisposing factorsContributory or predisposing factors

Infantile esotropia: perinatal complications Infantile esotropia: perinatal complications

(e.g. prematurity, birth injury, low birthweight). (e.g. prematurity, birth injury, low birthweight).

CARDINAL FEATURES CARDINAL FEATURES

General General Deviation may be constant, or it may come and goDeviation may be constant, or it may come and go May be present at birth, become apparent at a May be present at birth, become apparent at a

later age, or occur following an illness or accidentlater age, or occur following an illness or accident Horizontal deviations can be divided into two Horizontal deviations can be divided into two

broad categories - broad categories - esotropiasesotropias and and exotropiasexotropias. . Esotropia Esotropia designates a convergent horizontal designates a convergent horizontal strabismus (one eye turns in) and strabismus (one eye turns in) and exotropia exotropia designates a divergent horizontal strabismus (one designates a divergent horizontal strabismus (one eye turns out)eye turns out)

If angle of deviation remains same for all gaze If angle of deviation remains same for all gaze directions this a CONCOMITANT STRABISMUSdirections this a CONCOMITANT STRABISMUS


General General Misalignment of the visual axes of the two eyes Misalignment of the visual axes of the two eyes

may interfere with patient's ability to fuse and to may interfere with patient's ability to fuse and to develop normal binocular vision, this may cause develop normal binocular vision, this may cause suppression in one eye (suppression in one eye (amblyopia amblyopia or or lazy eyelazy eye) in ) in children and diplopia (children and diplopia (double visiondouble vision) in teenagers ) in teenagers and adultsand adults

Abnormal vertical head postures, e.g. head Abnormal vertical head postures, e.g. head turning, may develop to place the eyes in position turning, may develop to place the eyes in position of minimal deviation to restore single binocular of minimal deviation to restore single binocular visionvision


EsotropiaEsotropia

Accommodative esotropia (refractive Accommodative esotropia (refractive

accommodative esotropia) - an esodeviation due to accommodative esotropia) - an esodeviation due to

normal accommodation in uncorrected hyperopia normal accommodation in uncorrected hyperopia

(far-sightedness)(far-sightedness)

Uncorrected hyperope must exert accommodation Uncorrected hyperope must exert accommodation

to clear a blurred retinal image. Process of to clear a blurred retinal image. Process of

accommodation will stimulate convergence and accommodation will stimulate convergence and

strain fusional divergence. When fusional strain fusional divergence. When fusional

divergence is overcome, the eyes crossdivergence is overcome, the eyes cross


EsotropiaEsotropia

Patient with uncorrected hyperopia can see Patient with uncorrected hyperopia can see

either a single blurred image or a double image either a single blurred image or a double image

in which one image is clear and one is blurredin which one image is clear and one is blurred

Over time, the blurred image can be suppressed, Over time, the blurred image can be suppressed,

fixation can alternate, or, more commonly, fixation can alternate, or, more commonly,

amblyopia (lazy eye) can occuramblyopia (lazy eye) can occur


Infantile esotropiaInfantile esotropia

Inward deviation of the eyes noted before the Inward deviation of the eyes noted before the

patient reaches age 6 monthspatient reaches age 6 months

Infantile esotropia is not believed to be connatal, Infantile esotropia is not believed to be connatal,

but develops in the first few weeks or months but develops in the first few weeks or months

after birth after birth

Children who undergo surgical alignment at age 6 Children who undergo surgical alignment at age 6

months have a higher prevalence of coarse months have a higher prevalence of coarse

stereopsis than those who are corrected surgically stereopsis than those who are corrected surgically

at age 7-15 monthsat age 7-15 months


Infantile esotropiaInfantile esotropia

AmblyopiaAmblyopia is relatively common in patients with is relatively common in patients with

infantile esotropia Amblyopia should be suspected infantile esotropia Amblyopia should be suspected

strongly in patients with esotropia and strongly in patients with esotropia and

asymmetric inferior oblique activity, specifically in asymmetric inferior oblique activity, specifically in

the eye with more inferior oblique overactionthe eye with more inferior oblique overaction

Virtually all patients with infantile esotropia fail to Virtually all patients with infantile esotropia fail to

develop normal binocular vision and stereopsisdevelop normal binocular vision and stereopsis


ExotropiaExotropia

As many as 60% of patients who have As many as 60% of patients who have

exotropia may develop oblique muscle exotropia may develop oblique muscle

dysfunction, dissociated vertical deviation, and dysfunction, dissociated vertical deviation, and

amblyopiaamblyopia

Nystagmus is rareNystagmus is rare


Adult strabismusAdult strabismus

When strabismus occurs in an adult for the first When strabismus occurs in an adult for the first

time, it leads to double vision, or diplopiatime, it leads to double vision, or diplopia

Secondary to the inability of a person to use Secondary to the inability of a person to use

both eyes together (binocular vision) or other both eyes together (binocular vision) or other

unknown causesunknown causes

Most often, the poor-seeing eyes drift outwardMost often, the poor-seeing eyes drift outward

DIFFERENTIAL DIAGNOSIS DIFFERENTIAL DIAGNOSIS

Oculomotor nerve palsyOculomotor nerve palsy Extraocuiar muscle paralysis resulting from Extraocuiar muscle paralysis resulting from

destructive lesions in one or all of the cranial destructive lesions in one or all of the cranial

nerves results in failure of one or both eyes to nerves results in failure of one or both eyes to

rotate in concert with the other eye.rotate in concert with the other eye.

DIFFERENTIAL DIAGNOSIS DIFFERENTIAL DIAGNOSIS Oculomotor nerve palsyOculomotor nerve palsy

FEATURESFEATURES Diplopia from misalignment of visual axesDiplopia from misalignment of visual axes With unilateral third cranial nerve palsy, the With unilateral third cranial nerve palsy, the

involved eye usually is deviated down and out involved eye usually is deviated down and out (infraducted, abducted), and ptosis may be (infraducted, abducted), and ptosis may be present, which may be severe enough to cover the present, which may be severe enough to cover the pupilpupil

Pupillary dilatation can cause symptomatic glare in Pupillary dilatation can cause symptomatic glare in bright light (if ptotic lid does not cover the pupil)bright light (if ptotic lid does not cover the pupil)

Paralysis of accommodation causes blurred vision Paralysis of accommodation causes blurred vision for near objectsfor near objects

Glare sensation and photoaversion in bright lightGlare sensation and photoaversion in bright light


Abducens nerve palsyAbducens nerve palsy Cranial (abducens) nerve VI defect. Ipsilateral Cranial (abducens) nerve VI defect. Ipsilateral

lateral rectus, which is solely innervated by the lateral rectus, which is solely innervated by the

involved peripheral sixth cranial nerve, is involved peripheral sixth cranial nerve, is

affected.affected.


Abducens nerve palsyAbducens nerve palsy

FEATURESFEATURES Horizontal diplopia and an esotropia in primary Horizontal diplopia and an esotropia in primary

gaze gaze

Deviation greater when the patient fixates with Deviation greater when the patient fixates with

the paretic eye the paretic eye

Head-turn to maintain binocularity and binocular Head-turn to maintain binocularity and binocular

fusion, and to minimize diplopiafusion, and to minimize diplopia


Duane syndromeDuane syndrome Congenital ocular motiiity disorder characterized Congenital ocular motiiity disorder characterized

by limited abduction and/or limited adduction.by limited abduction and/or limited adduction.


Duane syndromeDuane syndrome

FEATURESFEATURES Upward or downward deviation may occur with Upward or downward deviation may occur with

attempted adduction due to a leash effect attempted adduction due to a leash effect

Face-turn with strabismus in primary position Face-turn with strabismus in primary position

Upshoot or downshoot during adduction Upshoot or downshoot during adduction

Vertical deviation in primary position Vertical deviation in primary position

Retraction during adduction Retraction during adduction

EnophthalmosEnophthalmos

MANAGEMENT ISSUES MANAGEMENT ISSUES

GoalsGoals Preserve visionPreserve vision

Straighten the eyesStraighten the eyes

Restore binocular (two-eyed) visionRestore binocular (two-eyed) vision

Prevent amblyopiaPrevent amblyopia

Prevent diplopia in adultsPrevent diplopia in adults

Obtain normal visual acuity in each eyeObtain normal visual acuity in each eye

Obtain and/or improve fusionObtain and/or improve fusion

MANAGEMENT ISSUES MANAGEMENT ISSUES

GoalsGoals Obtain favorable functional appearance of Obtain favorable functional appearance of

alignment of eyesalignment of eyes

The best optical correction that allows a The best optical correction that allows a

clear retinal image to be formed in each eye clear retinal image to be formed in each eye

is generally the starting point for all is generally the starting point for all

treatmentstreatments

SUMMARY OF THERAPEUTIC SUMMARY OF THERAPEUTIC OPTIONS OPTIONS

ChoicesChoices First choice is First choice is correctivecorrective lenses lenses and and prismsprisms. The . The

eye caregiver will determine whether or not a eye caregiver will determine whether or not a trial of spectacles can treat the strabismustrial of spectacles can treat the strabismus

Second choice is Second choice is patchingpatching. In cases of . In cases of amblyopia, early treatment with patching the amblyopia, early treatment with patching the normal eye is the mainstay of treatment, often normal eye is the mainstay of treatment, often associated with use of spectaclesassociated with use of spectacles

Third choice is Third choice is surgerysurgery. The eye caregiver may . The eye caregiver may determine that surgery is needed to correct the determine that surgery is needed to correct the strabismusstrabismus

SUMMARY OF THERAPEUTIC SUMMARY OF THERAPEUTIC OPTIONS OPTIONS

ChoicesChoices Fourth choice is Fourth choice is botulinum toxinbotulinum toxin. .

Chemodenervation using botulinum toxin as an Chemodenervation using botulinum toxin as an alternative to conventional incisional surgery is alternative to conventional incisional surgery is used in selected strabismic patients (those with used in selected strabismic patients (those with small-to-moderate degrees of horizontal ocular small-to-moderate degrees of horizontal ocular misalignment, postoperative residual strabismus, misalignment, postoperative residual strabismus, acute paralytic strabismus)acute paralytic strabismus)

Fifth choice is anticholinesterase Fifth choice is anticholinesterase mioticsmiotics. These . These can serve as temporary alternatives to corrective can serve as temporary alternatives to corrective glasses and glasses and bifocal lenses bifocal lenses for children with for children with accommodative esotropiaaccommodative esotropia

Documents

Strabismus Prof.Dr. Emel Başar İ.Ü. Cerrahpaşa Tıp Fakültesi, Göz Hastalıkları Anabilim Dalı