Download CARDINAL FEATURES Infantile esotropia

Strabismus
Prof.Dr. Emel Başar
İ.Ü. Cerrahpaşa Tıp Fakültesi,
Göz Hastalıkları Anabilim Dalı
SYNONYMS
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Squint
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Cross-eyed
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Wall-eyed
DESCRIPTION
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Misalignment of the eyes, such that both eyes are not
simultaneously directed at the same object
Esotropia is a common type of strabismus characterized
by inward deviation of one eye relative to the other
Infantile esotropia is inward deviation of the eyes noted
before the patient reaches age 6 months
Exotropia is a common type of strabismus characterized
by outward deviation of one eye
relative to the other
CONCOMITANT STRABISMUS
EPIDEMIOLOGY
Incidence and prevalence
PREVALENCE
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One of the most prevalent ocular problems among
children, affecting 50 in every 1000 US citizens, or
some 12 million people in a population of 245 million
Estimated prevalence of strabismus in the general
population is 20-60/1000
Of this, infantile esotropia is believed to affect about 1
% of full-term, healthy newborns and a much higher
percentage of newborns with perinatal complications
due to prematurity or hypoxic/ischemic encephalopathy
EPIDEMIOLOGY
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Demographics
AGE
Usually presents in patients aged 2-3 years
By definition, infantile esotropia is seen in infants before
age 6 months
GENDER
No gender predilection exists.
RACE
No racial predilection exists.
GENETICS
It is strongly believed that a genetic component exists, but
a solid basis for linkages among family members is still to
be established
Around 20-30% of children born to a strabismic parent will
eventually develop strabismus
CAUSES OF STRABISMUS
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Common causes
Exact cause of infantile esotropia remains unknown
Results from paralysis of one or more ocular muscles;
may be caused by a specific oculomotor nerve lesion
(Paralytic Strabismus)
Disuse of an eye, as in cases of severe refractive error
or impaired vision due to disease, may also result in
strabismus
Ambiyopia or lazy eye (reduced visual acuity caused by
an abnormal visual experience early in life) may occur
in strabismus, usually due to cortical suppression of the
image in the deviating eye to avoid confusion and
diplopia
CAUSES OF STRABISMUS
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Rare causes
Patients with craniofaciai syndromes, ocular albinism,
midline defects, and cerebral palsy may present with
congenital exotropia.
CAUSES OF STRABISMUS
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Serious causes
A specific oculomotor nerve lesion may cause paralysis
of one or more ocular muscles
In children, such a nerve lesion may be caused by
cerebral palsy, Down syndrome,hydrocephalus, or brain
tumors
In adults, nerve lesion may be caused by stroke,
diabetes, cardiovascular disease, tumors, or trauma
If there is a cranial nerve lesion the strabismus it is
paralytic
CAUSES OF STRABISMUS
Contributory or predisposing factors
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Infantile esotropia: perinatal complications
(e.g. prematurity, birth injury, low birthweight).
CARDINAL FEATURES
General
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Deviation may be constant, or it may come and go
May be present at birth, become apparent at a later
age, or occur following an illness or accident
Horizontal deviations can be divided into two broad
categories - esotropias and exotropias. Esotropia
designates a convergent horizontal strabismus (one eye
turns in) and exotropia designates a divergent
horizontal strabismus (one eye turns out)
If angle of deviation remains same for all gaze
directions this a CONCOMITANT STRABISMUS
CARDINAL FEATURES
General
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Misalignment of the visual axes of the two eyes may
interfere with patient's ability to fuse and to develop
normal binocular vision, this may cause suppression in
one eye (amblyopia or lazy eye) in children and diplopia
(double vision) in teenagers and adults
Abnormal vertical head postures, e.g. head turning,
may develop to place the eyes in position of minimal
deviation to restore single binocular vision
CARDINAL FEATURES
Esotropia
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Accommodative esotropia (refractive accommodative
esotropia) - an esodeviation due to normal
accommodation in uncorrected hyperopia (farsightedness)
Uncorrected hyperope must exert accommodation to
clear a blurred retinal image. Process of
accommodation will stimulate convergence and strain
fusional divergence. When fusional divergence is
overcome, the eyes cross
CARDINAL FEATURES
Esotropia
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Patient with uncorrected hyperopia can see either a
single blurred image or a double image in which one
image is clear and one is blurred
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Over time, the blurred image can be suppressed,
fixation can alternate, or, more commonly, amblyopia
(lazy eye) can occur
CARDINAL FEATURES
Infantile esotropia
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Inward deviation of the eyes noted before the patient
reaches age 6 months
Infantile esotropia is not believed to be connatal, but
develops in the first few weeks or months after birth
Children who undergo surgical alignment at age 6
months have a higher prevalence of coarse stereopsis
than those who are corrected surgically at age 7-15
months
CARDINAL FEATURES
Infantile esotropia
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Amblyopia is relatively common in patients with
infantile esotropia Amblyopia should be suspected
strongly in patients with esotropia and asymmetric
inferior oblique activity, specifically in the eye with more
inferior oblique overaction
Virtually all patients with infantile esotropia fail to
develop normal binocular vision and stereopsis
CARDINAL FEATURES
Exotropia
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As many as 60% of patients who have exotropia may
develop oblique muscle dysfunction, dissociated
vertical deviation, and amblyopia
Nystagmus is rare
CARDINAL FEATURES
Adult strabismus
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When strabismus occurs in an adult for the first time, it
leads to double vision, or diplopia
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Secondary to the inability of a person to use both eyes
together (binocular vision) or other unknown causes
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Most often, the poor-seeing eyes drift outward
DIFFERENTIAL DIAGNOSIS
Oculomotor nerve palsy
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Extraocuiar muscle paralysis resulting from destructive
lesions in one or all of the cranial nerves results in
failure of one or both eyes to rotate in concert with the
other eye.
DIFFERENTIAL DIAGNOSIS
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Oculomotor nerve palsy
FEATURES
Diplopia from misalignment of visual axes
With unilateral third cranial nerve palsy, the involved
eye usually is deviated down and out (infraducted,
abducted), and ptosis may be present, which may be
severe enough to cover the pupil
Pupillary dilatation can cause symptomatic glare in
bright light (if ptotic lid does not cover the pupil)
Paralysis of accommodation causes blurred vision for
near objects
Glare sensation and photoaversion in bright light
DIFFERENTIAL DIAGNOSIS
Abducens nerve palsy
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Cranial (abducens) nerve VI defect. Ipsilateral lateral
rectus, which is solely innervated by the involved
peripheral sixth cranial nerve, is affected.
DIFFERENTIAL DIAGNOSIS
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Abducens nerve palsy
FEATURES
Horizontal diplopia and an esotropia in primary gaze
Deviation greater when the patient fixates with the
paretic eye
Head-turn to maintain binocularity and binocular fusion,
and to minimize diplopia
DIFFERENTIAL DIAGNOSIS
Duane syndrome
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Congenital ocular motiiity disorder characterized by
limited abduction and/or limited adduction.
DIFFERENTIAL DIAGNOSIS
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Duane syndrome
FEATURES
Upward or downward deviation may occur with
attempted adduction due to a leash effect
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Face-turn with strabismus in primary position
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Upshoot or downshoot during adduction
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Vertical deviation in primary position
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Retraction during adduction
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Enophthalmos
MANAGEMENT ISSUES
Goals
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Preserve vision
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Straighten the eyes
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Restore binocular (two-eyed) vision
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Prevent amblyopia
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Prevent diplopia in adults
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Obtain normal visual acuity in each eye
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Obtain and/or improve fusion
MANAGEMENT ISSUES
Goals
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Obtain favorable functional appearance of
alignment of eyes
The best optical correction that allows a clear
retinal image to be formed in each eye is generally
the starting point for all treatments
SUMMARY OF THERAPEUTIC OPTIONS
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Choices
First choice is corrective lenses and prisms. The eye
caregiver will determine whether or not a trial of
spectacles can treat the strabismus
Second choice is patching. In cases of amblyopia, early
treatment with patching the normal eye is the
mainstay of treatment, often associated with use of
spectacles
Third choice is surgery. The eye caregiver may
determine that surgery is needed to correct the
strabismus
SUMMARY OF THERAPEUTIC OPTIONS
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Choices
Fourth choice is botulinum toxin. Chemodenervation
using botulinum toxin as an alternative to conventional
incisional surgery is used in selected strabismic
patients (those with small-to-moderate degrees of
horizontal ocular misalignment, postoperative residual
strabismus, acute paralytic strabismus)
Fifth choice is anticholinesterase miotics. These can
serve as temporary alternatives to corrective glasses
and bifocal lenses for children with accommodative
esotropia