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Sensory Esotropia
Strabismus
is the direct consequence of a primary sensory
deficit in one eye, and in such cases the term
sensory strabismus
is used.
The
most common causes
of sensory esotropia are injuries, corneal opacities, congenital or
traumatic unilateral cataracts, macular lesions,
and optic atrophy.
In the past it was wrongly
thought that whether or not a sensory esotropia
or exotropia developed depended on the age of
the patient at the time of visual acuity
decrease in one eye. It is not entirely clear
why some patients become esotropic and others
exotropic when they lose sight in one eye.
Sensory esotropia is
usually comitant; however, patients with a
long-standing sensory esotropia may show
limitation of abduction. Forced duction tests in
such patients reveal restriction of passive
abduction, a finding that must be interpreted as
evidence for contracture of the medial rectus or
the conjunctiva, or both, and Tenon’s capsule.
Therapy
Treatment is directed toward
improving the cosmetic appearance by means of
surgical correction since, in most instances,
the nature of sensory esotropia precludes
restoration of binocular function.
Sensory esotropia
requires surgery, and
an operation
should not be discouraged because of the
possibility of recurrent esotropia or even
consecutive exotropia. If that occurs,
additional surgery can be performed. There is no
need for a child to go through adolescence with
a severe cosmetic handicap that will have a
negative psychological effect.
Depending on the degree of
the deviation, a recession of the medial rectus
muscle combined with resection of the lateral
rectus muscle is usually sufficient.
If the forced duction test
is positive, a bare scleral recession of the
nasal conjunctiva and Tenon’s capsule should be
carried out.
The surgical result in
sensory esotropia is less predictable than when
visual acuity is normal in each eye, and
adjustable sutures may be helpful in improving
the alignment postoperatively.
Surgical alignment of a
sensory deviation may create a stable result in
many patients, however
the esotropia may recur or a consecutive
exotropia may develop years after the first
operation. The surgeon is advised to inform
patients of this possibility.
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