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466 Theory and Practice of Squint and Orthoptics
be placed in the muscle belly and sutured to the
globe at its original insertion.
ii. Partial or complete severance of superior oblique
tendon and sheath may occur while attempting
to hook the superior rectus muscle. Therefore,
surgeon should be very careful while engaging
the superior rectus muscle. However, if this does
happen, following measures should be taken:
• Inferior oblique should be recessed, so that a
significant vertical deviation does not result.
• If the operation originally planned is resection
of the superior rectus muscle the surgeon
should decrease the amount of surgery he
planned to do.
• If the operation is recession of the superior
rectus, surgeon should increase the amount
of recession along with weakening of the
inferior oblique of the same side.
8. Operation on the wrong eye
Operation on the wrong eye is an embarrassing
complication, sometimes encountered by the
surgeon. The best way to avoid this complication is examination of the patient by the
surgeon himself in the morning before surgery.
• Operation on the horizontal muscles of the
wrong eye may many a time correct the
deviation in the affected eye; but undoubtedly
the patient and/or her/this guardians and
surgeon all are upset by this mistake.
• Operation on the vertical muscle of the wrong
eye is always serious because the misalignment will be exaggerated. If the mistake is
discovered immediately, it should be taken
care of in the operation theatre there and then.
However, if the mistake is discovered postoperatively, it should be managed like a new
fresh case of misalignment.
9. Bradycardia and cardiac arrest
Bradycardia is very common and often transient
due to stimulation of the oculocardiac reflex on
pulling the muscle (most commonly the medial
rectus). It can be tackled with intravenous
atropine or glycopyrrolate. Lignocaine 2% given
as a peribulbar or subtenon's block reduces the
incidence. Cardiac arrest can rarely occur as a
result of general anaesthesia especially in
children with subclinical or known cardiac
defects or myopathies.
POSTOPERATIVE COMPLICATIONS
1. Postoperative infections. Because of perfect
asepsis and better quality spatulated needles,
the incidence of postoperative infection have
tremendously decreased. However, though
quite rare, following infections are reported:
i. Endophthalmitis has been reported to occur
following squint surgery because of following
reasons:
• Introduction of an infectious organism
following sclerochorioretinal perforation.
• Extension of cellulitis of extraocular muscles.
Early diagnosis and energetic management
can save the useful vision.
ii. Orbital cellulitis, though rare but it has been
reported in the literature postoperative
complication of squint surgery.
iii. Localized suture abscess has also been reported,
possibly resulting from contaminated suture
material.
2. Suture reaction. Because of better quality
synthetic sutures, the reactions are now very
rare. However, suture reactions were common
with the organic suture material. They used to
occur as acute allergic reactions within 24 hours
to 7 days of strabismus surgery and as delayed
foreign body reaction after 6–8 weeks of surgery.
Acute reaction is characterized by conjunctival
hyperaemia, chemosis, itching and a dull red
smooth mass beneath the conjunctiva at the site
of muscle reattachment. It is treated by topical
steroid eyedrops.
3. Wound gaping with exposure of bare sclera
or Tenon's prolapse is seen on few occasions
following surgery. Small gapes are observed
while larger ones may require additional
suturing.
4. Conjunctival granuloma. Because of improved
suture material and microsurgical techniques,
the incidence of conjunctival granuloma has
decreased. Conjunctival granuloma occurs as
non-allergic foreign body reaction to suture
material, cotton fibres, glove powder, an eyelash
burried in the wound or Tenon's capsule
incarcerated into the wound. Conjunctival
granuloma is characterized by a localized
elevated hyperaemic conjunctival mass which
may sometimes be even pedunculated.
Treatment consists of topical steroid eyedrops.
Principles of Non-Surgical and Surgical Management of Strabismus
467
Sometimes, even surgical excision may be
required.
5. Conjunctival and Tenon's cyst. Conjunctival
inclusion cyst may occur following inadvertent
closure of the conjunctival epithelium in the
wound. It appears as a subconjunctival
translucent mass that develops several days to
weeks after strabismus surgery. Some
conjunctival cysts will resorb spontaneously.
When indicated, surgical treatment consists of
complete excision of the cyst.
6. Dellen. Dellen refers to a localized area of
corneal thinning due to dehydration. It is more
common following limbal approach.
Dellen is caused by local precorneal tear film
disturbance due to adjacent heaped up
conjunctiva leading to compacting of corneal
stromal layers. The condition is treated with
lubricating drops 4 to 6 times a day and taking
measures to relieve swelling adjacent to the
dellen.
7. Corneal ulcer, filamentary keratitis, reduced
endothelial cell count are other less frequent
corneal complications encountered after squint
surgery.
8. Anterior segment ischaemia. It is a rare but
potentially serious complication of extraocular
muscle surgery which occurs due to disruption
of blood supply to the anterior segment from
the anterior ciliary arteries.
Risk factors for anterior segment ischemia
include:
• Surgery on more than 2 rectus muscles,
especially including vertical recti.
• Patient age more than 40 years.
• Vascular risk factors like diabetes, hyper-
tension, hyperlipidemia and smoking.
• Multiple surgeries.
• Limbal conjunctival incision.
Clinical features. In anterior segment ischaemia,
cornea becomes oedematous with stromal
swelling and folds in Descemet's membrane.
Anterior chamber shows heavy flare and
cellular reaction. Lens may become cataractous.
Prevention of anterior segment ischaemia is most
important since its treatment is unsatisfactory.
Following measures have been recommended
for its prevention:
• All four rectus muscles should never be
disinserted simultaneously.
• Disinsertion of three muscles can be done
safely in children, but should always be
avoided in adults.
• In general, a waiting of at least 6 months in
adult patients after surgery on both horizontal
rectus muscles is recommended before
operating on the vertical recti.
• Techniques for preservation of anterior ciliary
vessels during extraocular muscle surgery
which have been recommended are as follows:
– Microdissection of the anterior ciliary
vessels from the muscle under operating
microscope.
– Modified rectus tucking procedure as a
strengthening procedure.
– Muscle splitting procedures. The reliability
of these procedures in preventing anterior
segment ischaemia is yet to be ascertained.
Treatment of anterior segment ischaemia
consists of:
• Topical steroids every 1–2 hour,
• Systemic steroids for about 0–15 days, and
• Topical atropine twice a day.
Prognosis. The anterior chamber reaction is
usually controlled with the above treatment.
However, iris atrophy and cataract usually occur
as sequelae of the anterior segment ischaemia.
Sometimes the eyeball may go into phthisis
bulbi.
9. Scleritis both sterile and infectious has been
reported as an infrequent complication
following strabismus surgery. Patients with
systemic diseases like autoimmune vasculitis are
more prone to develop necrotising scleritis. It is
a painful complications.
10. Refractive error changes mostly astigmatic
have been reported following strabismus
surgery. Possibly, these changes occur because
of corneal curvature alterations caused by the
temporary imbalance of the muscle forces.
11. Postoperative diplopia is a common occur-
rence following strabismus surgery for comitant
heterotropias. It may last from a few days, a few
weeks or even lifetime. Children are usually able
to suppress early and so diplopia is short lasting.
468 Theory and Practice of Squint and Orthoptics
While in adults, it may sometimes be troublesome. Therefore, all adults opting for correction
of strabismus, must be warned of this
complication.
12. Postoperative retinal detachment. Retinal
detachment has been reported as very
infrequent complication following strabismus
surgery. A missed scleroretinal perforation is
considered the probable cause.
13. Postoperative scarring. Scarring of the
conjunctiva and extraocular muscles can occur
postoperatively and result in restriction. The
affected muscles and conjunctiva may need
recession. Postoperative scarring of Tenon's
capsule may produce an L-deformity of the
inferior oblique and a J-deformity of a rectus
muscle or cicatricial advancement of a rectus
muscle (see page 368).
14. Adhesive syndrome has been reported to
occur following surgery on inferior oblique
muscle (see page 368).
15. Under- or overcorrections are the most
common postoperative complications of
strabismus surgery. Their management has been
discussed along with the surgical treatment of
different types of heterotropia.
16. Gaze incomitance. Gaze incomitance may
occur following in large recession large angle
strabismus. Gaze palsy is also a known complication of Kestenbaum procedure especially the
augmented procedure employed in patients
with congenital nystagmus.
17. Alteration in palpebral fissure
• Narrowing of palpebral tissue may occur with
following procedures:
– Vertical rectus muscle resections, because of
fascial attachments from the exterior surface
of the muscle and adjacent lid.
– A large recess-resect procedure on the
horizontal rectus muscle, especially in a
reoperation can cause slight narrowing of
palpebral tissue because of slight retraction
of the globe.
• Widening of the palpebral tissue may occur with
vertical rectus muscle recessions.
18. Psychological complications. A multitude
of psychologically rooted behavioural changes
have been reported following surgery in young
children and thus should be kept in mind. A few
such disorders include enuresis, stuttering,
night terrors etc.
POSTOPERATIVE CARE AFTER STRABISMUS
SURGERY
1. Immediate general care includes:
• Vital signs should be observed for at least
24 hours after the surgery, especially when it
has been performed under general anaesthesia.
• Antiemetics may be given, if required and diet
is limited.
• Analgesics are rarely required following
strabismus surgery, when required, usually
aspirin or ibuprofen will produce comfort.
2. Dressing. It is useful to apply pad and bandage
on the operated eye for at least 24 hours.
3. Topical antibiotics and steroids. Eyedrops
should be instilled 3 to 4 times a day and eye
ointment at night for 2 to 3 weeks following
surgery.
4. Oral antibiotics are usually given for a period
of 5–7 days. Though their role in preventing rare
complications like orbital cellulitis and
endophthalmitis is debatable but it definitely
saves the surgeons from legal complications in
case of any eventuality.
5. Oral anti-inflammatory drug may also be
given for a period of 3 to 4 days.
6. Warm compresses to reduce swelling have
also been recommended.
7. Restrictions for the patient are to avoid
swimming, playing in a sand box or other
possible sources of postoperative infection.
8. Discharge from the hospital. If every thing
goes well, patient may be discharged from the
hospital a day after surgery. Following tests
should be done before discharging the patient:
• Conjunctival incision site should be examined
to make sure that it is closed properly and the
sutures have not broken.
• Approximate alignment of the eyes should be
determined by cover test and Hirschberg's test.
• Version test should be performed to rule out
the possibility of slipped muscle.
• Presence of diplopia should be checked and if
found, the patient and or parents should be
Principles of Non-Surgical and Surgical Management of Strabismus
469
told that this is a good sign since it may be the
first step towards fusion.
9. Postoperative follow-up examinations. At the
time of discharge from hospital, patient and/or
parents are instructed to dress the eyes with
sterile water and to use the prescribed eyedrops
and ointment.
Most patients are seen within one week
postoperatively and then at weekly intervals for
the next 2 weeks. And after that at 2 weeks
intervals for the next 2 months. It must be
emphasized that patients should be followed
closely in the immediate postoperative period
since this is a critical time, if one is attempting to
achieve fusional results. It is during this period
that situation is most plastic and that new
characteristics of the motor and sensory systems
are taking place.
During each follow-up visit, following tests
should be performed:
• Visual acuity testing
• Tests for alignment of the eyes
• Ocular movements
• Diplopia, if present, is identified as to types
10. Postoperative orthoptic treatment. It will
vary depending upon the preoperative
parameters, operative results, type of squint, age
of the patient and has been discussed with
individual clinical entity.
OUTLINES OF STRABISMUS MANAGEMENT
HETEROPHORIA
Examination
1. Measurement of visual acuity.
2. Refraction and fundus examination.
3. Cover-uncover test.
4. Measurement of deviation.
• Prism and cover test
• Maddox rod test
• Maddox wing test
5. Assessment of ocular movements.
6. Measurement of amplitude of fusional con-
vergence.
7. Measurement of accommodation.
Line of treatment
Exophoria
1. Correct refractive error.
2. Equalize visual acuity, if necessary.
3. Improve positive fusional convergence.
4. Surgery, when indicated.
Esophoria
1. Correct refractive error.
2. Equalize visual acuity, if necessary.
3. Improve negative fusional convergence.
4. Miotics, when exercises not sufficient and
AC/A ratio is large.
5. Surgery, when indicated.
Hyperphoria
1. Correct refractive error
2. Equalize visual acuity, if necessary.
3. Prescribe prisms.
4. Surgery, when indicated.
Cyclophoria
1. Correct refractive error.
2. Equalize visual acuity.
3. Surgery—when torsion due to oblique muscle
defect is present.
HETEROTROPIAS
Examination
1. Test visual acuity
2. Refraction and fundus examination
3. Cover test
4. Measurement of deviation
– Synoptophore method
– Prism bar cover test (PBCT)
5. Assessment of ocular movements
6. Assessment of accommodation, convergence
and AC/A ratio
7. Assessment of fusional ability and amplitudes
of fusion
8. Assessment of binocular co-operation and
sensory anomalies.
Esotropia
Differential diagnosis
1. Infantile esotropia
a. Additional history
• Onset before the age of six months
470 Theory and Practice of Squint and Orthoptics
• Fixates with either eye
• Constant ET
b. Tests
• Abduction—reluctant but intact
• Measurements—large ET, V-pattern
• Cross-fixates—equal vision
• Cycloplegic refraction—small refractive error
• Versions—possible IO overaction
• Cover-uncover—possible DVD
2. Accommodative esotropia
a. Additional history
• E (T), N > D
• Eye preference
• Worse than when tired, concentrating
• Typical age of onset—18 months to 3 years
• Range of onset—7 months to 10 years
b. Tests
• P + C, CC + SC—accommodative component
• Cycloplegic refraction
– <4 D hyperopia, high AC/A
–>4 D hyperopia, normal AC/A
• Fusion, CC—excellent usually
• Vision—amblyopia frequently
3. LR palsy (CN VI)
a. Additional history
• Severe head/neck trauma
• ET greater to right gaze, left gaze, or both sides
• Head position to right or left
• Horizontal, diplopia, variable worse at distance
• Sudden onset of ET/diplopia
• Present since birth, if congenital
• Associated with facial nerve palsy (Moebius
or brainstem tumour)
• Associated with ear pain (Gradenigo)
• Worsens with fatigue (myasthenia gravis)
b. Tests
• Fusion with head position—recent onset
• Measurements—ET > right and/or left gaze
– ET D > N slight A tendency
• Measure with OD, OS fix—primary/secondary
deviation
• Versions/ductions, saccades—decreased LR
function
• Diplopia testing—horizontal, incomitant
young child may suppress
• Vision—possible amblyopia
• Forced ductions—negative
4. Duane's retraction syndrome type I
a. Additional history
• No trauma
• Lid fissure changes with gaze
• Abnormal head position
• Present since birth
b. Tests
• Versions, ductions—no abduction, lid fissure
narrows during adduction
• Fusion with head position—fusion often
• Vision—may have amblyopia
5. Consecutive esotropia
a. Additional history
• Previous surgery for XT
b. Tests
• Fusion with ET corrected—fusion usually if
X or X (T) preoperative.
6. Nystagmus compensation syndrome
a. Additional history
• Any nystagmus seen during abduction
• Large ET present since birth
• Cross-fixates turning head to see
b. Tests
• Krimsky—over-converges with "correcting
prism".
• Versions/ductions—jerk nystagmus in
abduction, o.u.
• Cross-fixation—does not move fixing eye out
of adducted position to mid-line.
7. Cyclic esotropia
a. Additional history
• 24, 48, or 96 hours schedule of alternation
between ET one cycle and straight next cycle
• Fairly sudden onset during childhood.
b. Tests
• ET day
• Fusion—may have diplopia initially, then
suppression/ARC
• PB + CT—large ET, comitant usually
• Straight day
• Fusion—excellent
• PB + CT—ortho or small exophoria
• Vision—may have amblyopia
Principles of Non-Surgical and Surgical Management of Strabismus
471
8. Strabismus fixus
a.Additional history
Long-standing ET
b.Tests
• Forced ductions—positive MR tightening
• Measurements—large ET, greater in R and L
gaze
• Versions/ductions—decreased abduction,
fixed adduction
• Vision—must cross-fixate and turn head to see
9. Divergence paralysis
a. Additional history
• General health—N raised intracranial pressure
• Infections, parasites, and travel abroad
• Trauma possible
b. Tests
• Divergence amplitudes—nearly non-existent
• Versions/ductions—full, abduction okay
• Diplopia testing—uncrossed, worse at distance
• Measurements—may fuse at near
• Vision—equal
Line of treatment
Refractive accommodative esotropia
1. Correct refractive error
2. Treat amblyopia, if necessary
3. Overcome suppression
4. Improve negative fusional convergence
5. Surgery should be avoided
Non-refractive accommodative esotropia
1. Treat amblyopia, if necessary
2. Bifocals with a +3 add over cycloplegic
refraction
3. Miotics, only if bifocals not accepted
4. Orthoptic treatment to over come suppression
and improve negative fusional convergence
Mixed accommodative esotropia
1. Correct refractive error, bifocals, if AC/A is
high
2. Treat amblyopia, if necessary
3. Orthoptic treatment to overcome suppression
and improve the negative fusional convergence.
4. Surgery only for the remaining nonaccommodative part of squint.
10. Accommodative effort syndrome
a. Additional history
• Near asthenopia, blurring, or diplopia
b. Tests
• NPA—normal
• PB + PC—E', possibly E (T)'
• Divergence amplitudes—poor
• Plus lenses for near—help relieve symptoms
11. Pseudoesotropia
a. Additional history
• Onset—usually since birth
• Incomitance
b. Tests
• Hirschberg/cover uncover—no deviation
• External—epicanthal folds frequently
• Angle kappa—negative
• Fusion—excellent, no suppression
• Versions/ductions—appears to have increasing
• ET to right and left gaze
Essential infantile esotropia
1. Correct refractive error
2. Amblyopia treatment, if necessary
3. Surgery by the age of 2 years
Essential late onset esotropia
1. Correct refractive error
2. Treat amblyopia, if necessary
3. Perform surgical correction
– Basic esotropia—recess/resect
– Convergence excess—bimedial recession
– Divergence insufficiency type—bilateral
lateral rectus resection.
Sensory esotropia
1. Correct refractive error
2. Cosmetic surgery, if necessary
Exotropia
Differential diagnosis
1. Primary exotropia
a. Additional history
• Intermittency
472 Theory and Practice of Squint and Orthoptics
• Worse at distance or near
• Worse with fatigue, illness
b. Tests
• Fusion—usually excellent
Measurements—exodeviation, usually comitant
Basic, divergence excess type, convergence
insufficiency type
• Vision—equal
• Convergence amplitudes—poor fusional
convergence amps
2. Infantile exotropia
a. Additional history
• Present since birth
• Eye preference
b. Tests
• Vision—decreased in non-preferred eye
• Health of eyes—no specific disease of eye
• Measurements—usually large; comitant XT
3. MR palsy/CN III palsy
a. Additional history
• Present since birth, if congenital
• Severe trauma
• General health—possible headaches,
myasthenia gravis
• Other signs—ipsilateral ptosis, mydriasis,
cycloplegia, hypodeviation, contralateral
body paralysis (Benedikt’s syndrome)
b. Tests
• Versions/ductions—decreased adduction
• Measurements—incomitant exodeviation,
greater in adduction
• Measure with OD, OS fix—primary and
secondary deviation
• Vision—possible amblyopia, cycloplegia
• Head position—present, if to attain fusion
4. Duane’s retraction syndrome type II
a. Additional history
• No trauma
• Lid fissure changes with gaze
• Abnormal head position
• Present since birth
b. Tests
• Versions/ductions—decreased adduction
with lid narrowing, abduction okay
• Head position—done to achieve fusion
• Fusion with head—often present position
• Vision—may be amblyopic
5. Sensory exotropia (due to blind eye)
a. Additional history
• Age of blindness in one eye (if over 7, likely
to go exo)
Constant non-alternating XT
b. Tests
• Vision—blind eye
• Krimsky measurements—fairly comitant XT
6. Consecutive exotropia
a. Additional history
• Previous surgery for ET
b. Tests
• Measurements—XT
Fusion—diplopia or suppression/ARC
7. Craniofacial anomalies
a. Additional history
• Alpert syndrome
• Crouzon syndrome
b. Tests
• Measurements —large XT, bilateral SO palsies
often
• Versions/ductions—IO, overaction, SO
under-action
• External—bilateral exophthalmos (Crouzon)
• Refraction—astigmatism (Alpert), progressive
hyperopia (Crouzon)
8. Convergence paralysis
a. Additional history:
• Trauma
• General health—recent neurological condition
possible
b. Tests
• Convergence amplitudes—nearly non-
existent
• Measurements—comitant exodeviation N>D
• Versions/ductions—full
• Diplopia—crossed, worse at near
• Fusion—at distance only
• Vision—equal
9. Internuclear ophthalmoplegia (INO)
a. Additional history
• Bilateral—systemic multiple sclerosis
Principles of Non-Surgical and Surgical Management of Strabismus
473
• Unilateral—vascular accident, inflammation,
infection, or tumour in brainstem, possibly
myasthenia gravis
b. Tests
• Versions/ductions—decreased adduction
with jerk nystagmus in abducted eye
• Convergence amplitudes—intact convergence
10. Pseudoexotropia
a. Additional history:
• Constant
b. Tests
• Krimsky/cover-uncover test. No eye
deviation
• Fusion—excellent, no suppression
• Angle kappa—positive
• Funduscopy—may have retinopathy of pre-
maturity with temporally dragged fovea
Line of treatment
Primary intermittent exotropia
1. Correct refractive error; myopia should be
fully corrected hypermetropia up to 2.0 DS need
not be corrected.
2. Orthoptic treatment:
• Antisuppression exercises
• Exercises for positive relative convergence
• Occlusion therapy
3. Prismotherapy in children where surgery is
to be postponed for some period.
4. Surgery is indicated, when:
• Exotropia occurs more than 50% working
hours
• Deviation exceeds 20D
• There develops secondary convergence
insufficiency with asthenopic symptoms.
• Suppression develops
• There occurs gradual deterioration of stereopsis.
• Age for surgery: Before 4 years
Primary constant exotropia
1. Surgical correction should be done as early
as possible.
2. Orthoptic treatment both before and after
surgery should be continued, if fusion ability can
be demonstrated.
Sensory exotropia
1. Correct any refractive error
2. Amblyopia therapy may be tried in children
with anisometropia or aphakia
3. Cosmetic surgery is the usual treatment.
Consecutive exotropia
1. Correct any refractive error
2. Assess state of binocular sensory cooperation
a. If normal regional correspondence and
bifoveal fusion can be demonstrated:
i. Overcome suppressions
ii. Improve fusional convergence
iii. Perform surgery
b. If bifoveal fusion cannot be demonstrated;
assess cosmetic appearance.
i. If good, leave alone
ii. If poor, perform cosmetic surgery.
Vertical and cyclodeviations
Differential diagnosis
I. Isolated CN palsy (SO most common)
a. Additional history
• Trauma, may be mild
• Head tilt
• Combined horizontal and vertical diplopia
• Diplopia/asthenopia worse to right and left
• Myasthenia gravis
b. Tests
• Fusion with head position—usually fuses
• PB CT, 9 positions—incomitant HT
• B3ST—isolates EOM palsy
• Versions/ductions
– SO: May show underactive SO, overactive IO,
inhibitional palsy of contralateral (IPC) SR
– IO: May show underactive IO, overactive
SO, IPC IR
– SR: May show underactive SR; overactive
IR, IPC SO
– IR: May show underactive IR, overactive
SR, IPC IO
• Vertical amplitudes—may exist, if congenital/
long-standing. No vertical amplitude, if recent
onset
• Subjective torsion
– May exist, if recent onset
– No torsion, if congenital/long-standing
palsy
474 Theory and Practice of Squint and Orthoptics
– SO, SR—extorsion
– IO, IR—intorsion
• Look at old photographs—old head tilt, if
congenital/long-standing
2. DVD
a. Additional history
• Associated with congenital/infantile ET
• One or both eyes seen to go up, neither eye
ever goes hypodeviation
• Intermittent HT, either eye
b. Tests
• Cover-uncover—either eye elevates under
cover without associated hypodeviation of the
fellow eye
• PBCT—difficult to measure, variable
• Versions/ductions—rule out IO overaction as
“cause”
• Red glass test
• Bielschowsky's phenomenon—positive
3. Brown’s syndrome
a. Additional history
• Trauma to trochlear region of globe
• Sinus, orbital surgery
• Juvenile rheumatoid arthritis
• Present since birth, if congenital
b. Tests
• Versions/ductions—no elevation of globe in
adduction. Eye elevates easily in abduction
• Forced ductions—restriction of globe up and in
• Fusion—often fuses in downgaze
• Vision—amblyopia may or may not be present
• Krimsky—hypotropia of affected eye, when
up and in
4. Blow-out fracture
a. Additional history
• Blunt trauma—orbital fracture
• Diplopia/discomfort worse in upgaze often
b.Tests
• Ductions/versions
– Hypotropia worsens towards upgaze
– Restrictions of ductions—upgaze, may be
down, right, or left gaze
• Forced ductions—restriction of globe, upgaze
usually
• X-ray/CT scan—orbital fracture, floor
frequently, or nasal wall
• Diplopia field—often has region of single
binocular vision
• Exophthalmometry—often affected eye
enophthalmic
5. Double elevator palsy (DEP)
a. Additional history
• Present since birth
• Ptosis on affected side
• Chin up head position
• No trauma
b. Tests
• Fusion with chin up—possible fusion
• Versions/ductions—constant hypotropia of
affected eye
• Forced ductions—no restrictions of elevation
unless very long-standing
• External—pseudoptosis on affected side
6. Graves' ophthalmopathy
a. Additional history
Thyroid dysfunction in past or present
b. Tests
• Ductions/versions—restriction of upgaze
(IR), lateral gaze (MR), or any EOM
• Forced ductions—positive for restriction
• Fusion with head position—usually has fusion
• Diplopia—variable, vertical > horizontal
7. Pseudohypertropia
a. Additional history
b. Tests
• Cover-uncover—no deviation
• Lift lid—appearance of HT disappears
• Assess pupils—possible asymmetry
• Document with photos—no deviation by light
reflex
Line of treatment
Comitant vertical deviatons
1. Treat amblyopia and suppression
2. Prescribe prism for deviations up to 10D:
– Minimum prismatic power that provides
comfortable DSV should be prescribed.
– Distribute prism power equally in two eyes
with base-down in front of the hypertropic
and base-up infront of hypotropic eye.
3. Surgery is indicated for deviations larger than
10D.
Principles of Non-Surgical and Surgical Management of Strabismus
475
• Vertical transplantation of horizontal rectus
muscle insertion is sufficient for 10–14D
vertical deviations associated with horizontal
tropia.
• Recession of appropriate vertical muscle (3 to
4 mm) is required for larger deviations of 15D
to 25D.
Dissociated vertical deviations
For significant cosmetic problem due to DVD,
treatment is mainly surgical following
operations may be performed:
1. Faden operation with superior rectus
recession.
2. Large recession of the superior rectus muscle.
3. Resection of the inferior rectus muscle.
4. Recess-resect procedure on superior and
inferior rectus muscles.
5. Recession of the inferior oblique with
anteriorization of its insertion.
Inferior oblique overaction
In significant cases, inferior oblique weakening
should be done by any of the following
procedures:
1. Disinsertion
2. Myectomy
3. Extirpation
4. Recession
5. Recession with anterior transposition
Superior oblique overaction
1. Superior oblique tenotomy
2. Superior oblique lengthening
Cyclodeviation with vertical deviation
1. Weakening of the offending inferior oblique
muscle should be done, when excyclodeviation
with hyperdeviation is associated with
secondary overaction of inferior oblique.
2. Tucking of superior oblique muscle should
be done, when excyclodeviation with hyperdeviation occurs in the field of paretic
superior oblique without overaction of inferior
oblique.
3. Bilateral tucking of superior oblique is
required in patients with bilateral superior
oblique palsy producing V-pattern esotropia
and excyclodeviation.
Excyclodeviations with no vertical deviation
1. Harada-Ito procedure (anterolateral
advancement of superior oblique tendon)
2. Nasal transposition of inferior rectus muscle
in patients with congenital absence of superior
oblique tendon or in those where it has already
been tenotomized.
3. Temporal transpositioning of superior rectus
muscle.
Incyclodeviation with no vertical deviation
Temporal transposition of inferior rectus along
with nasal transposition of the superior rectus
muscle.
Incomitant strabismus
A- and V-pattern horizontal tropias
1. Treatment of V-pattern esotropia
i. For correction of horizontal deviation in primary
position:
– Bilateral medial rectus recession or
– Medial rectus recession and lateral rectus
resection
ii. For correction of V-pattern:
– Inferior oblique muscle weakening–when
overacting, otherwise
– Infraplacement of medial recti or infra-
placement of MR and supraplacement of
LR.
2. Treatment of A-pattern esotropia
i. When superior oblique overaction is
associated—bilateral tenotomy of superior
oblique muscles should be performed and
either bilateral medial rectus recession or
recess-resect procedure should be
performed for correction of horizontal
deviation in the primary gaze after making
adjustment for 10–15 prism dioptres which
is corrected by bilateral superior oblique
tenotomy. Alter-natively, horizontal rectus
muscle surgery may be deferred for a later
date.
ii. When superior oblique overaction is not
present, the treatment of choice is either
bilateral medial rectus recession with
supraplacement of the insertions, or
combined supraplacement of the medial
rectus and infraplacement of the lateral
rectus muscle with a recess-resect procedure.