Strabismus
and Eye Muscle Surgery
G. Vike Vicente M.D.
Eye Doctors of Washington
G.Vicente,MD
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Dr. Vicente Strabismus review outline:
Horizontal strabismus
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Anatomy review
Nomenclature review
Accommodative esotropia
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Infantile esotropia
Viral & Diabetic esotropia
Sensory strabismus
Pseudostrabismus
Duane’s syndrome
Exotropia
Convergence insufficiency
Phorias
Tropias
Eye Muscle Surgery
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Pediatric Bifocals?
Recession
Resection
Vertical Strabismus
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Parks’ Three step test
Superior Oblique Palsy
Brown Syndrome
Inferior Oblique Overaction
DVD- Dissociated Vertical Deviation
Blow out Fracture
Skin
Conjunctiva
Tenon’s layer
Eye Muscles
Left eye
G.Vicente,MD
Superior Oblique/Trochlear Muscle
Eye Muscles
Left eye
Superior Rectus Muscle
Medial Rectus Muscle
Lateral Rectus Muscle
Inferior Rectus Muscle
Inferior Oblique Muscle
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Nomenclature
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Orthorphoria
o
Esophoria
E
Esotropia
ET
Intermittent Esotropia E(T)
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Exophoria
X
Exotropia
XT
Intermittent Exotropia X(T)
At near
X(T)’
convergent
divergent
• Right HypertropiaRHT
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Right Hypertropia
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Strabismus Why is it Important?
• Preserving Stereo acuity 8 yo with
worsening X(T) Intermittent Exotropia.
• Enlarging Visual field
– for Pts with ET.
• Appearance
– Would you hire me?
– Would you date me?
– Is there something wrong with you?...
• Diplopia
G.Vicente,MD
Strabismus Why operate?
Diplopia
Can be a very debilitating symptom affecting lifestyle and
quality of life.
G.Vicente,MD
Accommodative esotropia
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Typically presents around age 2 years, may present
acutely.
Always put +3.00 sph OU when you see an ET for the
first time.
If its improved or resolved think Accom ET!
Why is there ET with Accommodation?
Eyes will usually converge when accommodation is
attempted.
If high hyperope then must accommodate, if
accommodating then will converge, cross, specially at
near.
Accommodative ET
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Use cyclogyl to measure Rx (wait 40 minutes)
Recheck 4 weeks later with glasses,
If still some ET present, use Atropine to make
sure you measured the full CRx
Tell parents they eyes will continue to cross
every time the glasses come off.
Always give full CRx, cycloplegic refraction for
suspected Accom ET.
Child might not like full CRx 
Use Atropine when using hyperopic glasses for
the first time, it will break the accommodative
spasm and allow the pt to get used to the
glasses.
emmetropia
CRx = +5D hyperopia, no accommodation
+3D
+3D
+5D
+3D
+5D hyperopia
(lets say the pt is able to accommodate 3D,
so effectively they are only +2D hyperope)
+5D Rx +3D accom spasm = +8D, pt is only a +5.00 so
Pt ends up feeling like a -3.00D myope with your Rx
My son does not like the glasses you recommended,
The optician was right, they are too strong
+5D
+5D
+3D
+0D
With Atropine, no accommodation,
no convergence for distance
Pt happy, MD happy
Accommodative ET, AC/A
AC/A =
Accommodative convergence / accommodation
 An accom ET crosses because he/she has normal AC/A.
 Ie of high AC/A:
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an emmetrope, WRx = plano OU pt
At Distance they are ortho
At near they are 25PD ET’
They are over converging for a normal amount of accommodation.
This is a high AC/A ratio.
AC/A
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Example of a pt with low AC/A?
who underconverges?
+8.00 hyperope who is ortho at near and
distance.
They have adapted to their hyperopia by
under converging.
Infantile Esotropia Syndrome
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Aka congenital esotropia
Esotropia usually present by age 6
months
Not improved with hyperopic Rx
Most pts will never have good stereo
Associated with inferior oblique over
action
And DVD, dissociated vertical
deviation.
The 2 latter conditions may not be
present initially must remember to
warn parents that if they occur in the
future it is not the surgeon’s fault.
Infantile esotropia continued
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Must rule out other causes
CN 6 palsy from birth? Often spontaneous
resolution
Remember some variable, intermittent
strabismus is expected until 4 months of
age.
Esotropia associated with Viral
illness
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Often self limited, will spontaneously
resolve in 3-6 months.
Acute
Not improved with hyperopic glasses.
Consider ruling out neoplastic causes.
Treat/prevent amblyopia in the mean time
Esotropia associated with Diabetes
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Abducens, lateral, CN 6 usually affected.
Isolated unilateral palsy
Ischemic
Usually resolves after 4-6 months.
Consider Botox in the meantime, to which
muscle…
The medial rectus
Botox injection to Medial Rectus
For temporary lateral rectus ischemic palsy
Sensory strabismus - Peds
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Young pts with poor monocular vision will
often develop esotropia in that eye.
OKAP NOTE::::::::
DOES YOUR PEDS PT HAVE ESOTROPIA
BECAUSE THEY CAN NOT SEE OUT OF
THAT EYE?
WHY? CATARARCT, RETINOBLASTOMA,
MACULAR SCAR, ANISOMETROPIA?
Sensory strabismus- adults
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Adult with poor monocular
vision will often develop
exotropia.
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Think dense cataract X 5
years
Warn pt about possible post
op diplopia and need for
strabismus surgery
Pt may have lost the ability to
fuse.
Think monovision, or
unilateral under correction
Lasik pt who had undiagnosed
intermittent exotropia.
Pseudo ET
Orthophoria
Esotropia
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Initially the baby has
a “button nose, with
a very flat nasal
bridge.
The baby lids cover
the medial white part
of the eyes causing
the appearance of
the eyes being
crossed.
As the nasal bridge
develops and grows
forward it will drag
the medial portion of
the lids inward
reducing the
appearance of the
eyes being crossed.
1
Pseudo ET
G.Vicente,MD
Initially the baby has
a “button nose, with
a very flat nasal
bridge.
The baby lids cover
the medial white part
of the eyes causing
the appearance of
the eyes being
crossed.
As the nasal bridge
develops and grows
forward it will drag
the medial portion of
the lids inward
reducing the
appearance of the
eyes being crossed.
2
Pseudo ET
G.Vicente,MD
Initially the baby has
a “button nose, with
a very flat nasal
bridge.
The baby lids cover
the medial white part
of the eyes causing
the appearance of
the eyes being
crossed.
As the nasal bridge
develops and grows
forward it will drag
the medial portion of
the lids inward
reducing the
appearance of the
eyes being crossed.
3
Pseudo ET
G.Vicente,MD
Initially the baby has
a “button nose, with
a very flat nasal
bridge.
The baby lids cover
the medial white part
of the eyes causing
the appearance of
the eyes being
crossed.
As the nasal bridge
develops and grows
forward it will drag
the medial portion of
the lids inward
reducing the
appearance of the
eyes being crossed.
4
Pseudo ET
G.Vicente,MD
Exotropia
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Intermittent is very common
How symptomatic are they?
Make sure they have BCVA glasses
Diplopia?
Often familial, so what? Dad had it too.
“What hump?”
Intermittent exotropia can breakdown over time,
check serial stereo. If worsening think surgery.
Most common time of pediatric surgery is 7 years old.
Can the pt converge?
Convergence insufficiency
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Seen in kids who have trouble reading
Adults with Parkinson’s disease
Consider
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Convergence exercises by a pediatric optometrist, or
at home exercises with special software
Decreasing add in bifocals to extend reading distance
(holding reading material further away)
Prisms, may used at times.
Nomenclature
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Orthorphoria
o
Esophoria
E
Esotropia
ET
Intermittent Esotropia E(T)
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Exophoria
X
Exotropia
XT
Intermittent Exotropia X(T)
At near
X(T)’
convergent
divergent
• Right HypertropiaRHT
G.Vicente,MD
Cover – Uncover test
Orthophoria, normal
No complaints, asymptomatic
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Cover – Uncover test
Esophoria, abnormal, common
Only seen when eye is covered
Often asymptomatic, no complaints
Note OS does not move.
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Cover – Uncover test
Exophoria, abnormal, common
Only seen when eye is covered
Note OS does not move
Often asymptomatic, no complaints.
G.Vicente,MD
Alternate cover test
• Remember to allow the pt time to fixate on
the target, give them a minute.
• Then quickly cover the other eye to
prevent the pt from regaining fusion.
• But do not go back and forth quickly
because the pt will not have time to
refixate.
Alternate Cover test
Exotropia, intermittent
May be visible with or without
alternate cover
May have intermittent diplopia,
especially when tired or sick
Mom sees misalignment every
now and then.
G.Vicente,MD
Alternate Cover test
Exotropia, Constant
May be visible with or without
alternate cover
May or may not have constant
diplopia
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Cover Uncover test
Left Exotropia, Constant
May be visible with or without
alternate cover
Right eye preference
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Cover Uncover test
Left Exotropia, Constant
May be visible with or without
alternate cover
Right eye preference
Note: no eye movement, so be
sure to check both sides
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Normal Convergence
Convergence Insufficiency
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Constant Strabismus
Workup, acute presentation, nerve palsy
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(Case of newly acquired left CN 6 in a 55 yo male)
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Ischemic, GCA
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Neoplastic
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Invasive
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Paraneoplastic
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Compressive
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Nerve regeneration
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Longstanding breakdown.
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Sensory
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Degenerative CNS, Parkinson’s, MS
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Infectious
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Myositis (trichinosis)
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Iatrogenic
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Post non-strabismus surgery
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Cataract, retrobulbar blocks (nerve damage vs. contracture)
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Glaucoma, valves
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Lasik
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Mechanical
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Trauma
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Blow out Fracture
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Tumor
G.Vicente,MD
More Types of Strabismus
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Convergent, Esotropia
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Accommodative
Congenital or infantile
Acquired, CN 6 palsies
Divergent, Exotropia
Vertical, Torsional and Oblique
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Parks 3 Step test
Superior Oblique Palsies
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Tucks vs. IO recessions
Inferior Oblique Over action (V patterns)
DVD’s Dissociated Vertical Deviation
Complex Cases
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Adjustable vs Fixed sutures.
Re-ops
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Different measurements based on eye fixation
Optics
Angle Kappa
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How much to operate…
Alternate Cover test with Prism
Exotropia, Constant
Use prism to quantitate the
deviation.
Change prism power until
movement is neutralized.
Use this number to plan surgery
G.Vicente,MD
Exotropia
• Remember to measure while fixating at a
far distance.
• Also use +3.00 sph in front of each eye to
eliminate the accommodative convergence
component at distance.
• Consider 30 minute patch test to break
fusion and really see how bad the XT can
get.
How much to operate?
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How much to
operate
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Tables:
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Personal experience
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Dosages (surgical)
bilat , 2 muscles
ie for ET 40PD recess 5.5mm both MR
ET
XT
PD Rec Rst Rec Resect
15 3
3
4
2.5
20 3.5
4
5
3
25 4
5
6
4
30 4.5
6
7
5
35 5
7
7.5
5.5
40 5.5
7.5 8
6
50 6
8
9*
7
60 6.5
8.5 10*
8
Where to operate?
Option A: recess, loosen bilateral MR Medial Recti.
Option B: recess Left MR and resect, tighten Left Lateral Rectus LLR
RMedial Rectus
LMedial Rectus
L Lateral Rectus
G.Vicente,MD
Large ET (65PD) , bilateral MR
recession, and LLR resection
3d
post op
preop
1 month post op
G.Vicente,MD
How much to operate
-Patient preference
 Case of monocular 85 yo
BF with sensory XT
 one eye or two?
 Pt wished to not have OD
operated, understood risk
of under correction.
 Therefore only recessed
LMR 7mm and LLR 6mm.
 Pt had some residual XT
15-20 PD, but was happy,
therefore surgeon was
happy too.
G.Vicente,MD
Surgical Notes
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Sutures:
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What to expect after surgery
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Some double vision is normal for the first few weeks after eye
muscle surgery.
Precaution:
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Most stitches used in eye surgery are thinner than human
hairs.
They will dissolve on their own over 6 weeks. They may make
your eye feel scratchy for the first few weeks.
The antibiotic ointment and a cool compresses will alleviate
this symptom if it occurs.
Adjustable sutures
General post op hygiene
Eye rubbing
Can my child swim after his or her eye surgery?
Length of surgery and recovery
G.Vicente,MD
Notes on Anesthesia
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Notes on Anesthesia
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General
Pediatric anesthesia doctors
Risk of Gen. Anesthesia in children
Primary MD clearance
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Complications and Risks or surgery
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Infection (1 in 3 years, Tx oral Abx)
Nausea (Tx: Phenergan, etc.)
Blood loss
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(what blood loss, maybe a little more than corneal
surgery)
Loss of sight? (globe perforation)
Scar tissue
Diplopia
Residual or consecutive strabismus
Oculo-Cardiac Reflex – Bradycardia
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Tx: Atropine
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When to operate? Or …When NOT to operate?
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Prisms
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Fresnels
Permanent prisms
Occlusion (non-operable, CNS disease)
BCVA (sharp image will often help pt fuse)
G.Vicente,MD
When not to operate cont.
• Botox
– best for small, new, noncontractile strabismus, ie ischemic CN 6
palsy.
– Or very variable strabismus ie cerebral palsy, to prevent
contracture and save time.
• Exercises, best for convergence insufficiency X(T)’.
• Small Magnitude (<8 PD)
• Tolerability, symptoms
– head position, career, lifestyle
• Surgeon aggressiveness, cut, cut, cut
• Pre-existing Amblyopia
– (how much to treat before surgery?)
• Angle Kappa pseudo XT…