A and V Patterns and Other Types of

Strabismus

Paviglianiti / January 21, 2010

A and V Patterns Horizontal deviations that change in magnitude in upgaze and

downgaze A or V patterns reportedly in 15-25% of all horizontal strabismus IOOA assoc with V patterns SOOA assoc with A patterns Sometimes, if vertical muscles underacting (eg SR) then their tertiary

adducting effect in upgaze will decrease, giving a V pattern; underacting IR will decrease its tertiary adduction in downgaze, giving an A pattern (both SR and IR are tertiary adductors)

Pts with Aperts/Crouzons have V patterns since their orbits are excyclotorted

Technically, need a difference between upgaze vs downgaze of at least 10d in A pattern; 15d in V pattern (I use 15 for both)

If obliques are overacting, weaken them; if not, do MALE horizontal transposition by ½ tendon width…rules apply regardless of whether you are weakening or tightening or whether surgery on 2 eyes or R/R on 1.

Special Forms of Strabismus

Duanes Syndrome Möbius Syndrome Brown’s Syndrome Thyroid Eye Disease Congenital Fibrosis Syndrome Progressive External Ophthalmoplegia (PEO) Myasthenia Internuclear Ophthalmoplegia (INO) Congenital Oculomotor Apraxia Congenital / Acquired 3rd, 4th, 6th palsies

Concomitant vs IncomitantConcomitant Strabismus:

The measurements are the same in all fields of gaze (numbers on the tictactoe board are the same in all the boxes) AND the range of mvt of the eyes is full

Incomitant Strabismus Measurements different in different fields of

gaze

Duane’s SyndromeType I =>reduced abductionType II => reduced adductionType III => reduced abd and add

Clinically, this classification scheme is of little use

Duane’s Syndrome/Type I Can’t abduct, so usually esotropic in primary

position, sometimes with compensatory head turn for fusion

Usually girls More often left eye, but bilateral 20% On attempted abduction, involved lids widen

Involved lids widen on attempted mvt toward deficit On adduction, involved lids narrow and globe

retracts into orbit, and there are upshoots and downshoots Involved lids narrow on attempted mvt away from

deficit; upshoots/downshoots on involved eye with attempted mvt away from deficit

Bilateral Duane’s I

Bilateral Duane’s; note lid widening on attempted abduction

Note the working adducting eye with lids narrowing and globe retraction

Duane’s SyndromeType II

Limited adduction, so XT in primaryDdx includes INO, but INO has no lid

fissure widening on attempted movement toward the deficit

Duane’s II

Note full abduction, limited adduction with upshoot on attempted right gaze

Could confuse with INO or IOOA

Duane’s SyndromeType III

Limited abduction and adduction, so usually ortho in primary

Duane’s Syndrome Usually NOT inherited (sporadic), but 10% there is

auto dominant inheritance Since bilateral 20%, ddx includes congenital

esotropia with tight medial recti, which don’t allow full abduction

Used to be thought it was caused by hypoplasia of 6th nerve nucleus, with the 3rd nerve taking over innervation of the LR in an abnormal way; this isn’t proven and exact cause of Duane’s still mysterious

Ocular associations: ptosis of involved side; cataracts, iris heterochromia, iris/retina coloboma

Duane’s SyndromeAssociations

Thalidomide exposure (West Germany 1957-1962: 30% of these babies had Duane’s

Possible fetal alcohol link (so teratogenicity during 4th to 5th weeks of gestation possible?)

Deafness in 10% of Duane’s (although I haven’t noted that clinically)

Duane’s + deafness + Klippel/Feil spine anomaly (short neck, reduced mvts, low posterior hairline) => WILDERVANKS (cervico-oculo-acoustic)

Goldenhar’s Marcus-Gunn jaw winking and crocodile tears (other

forms of aberrant innervation)

Duane’s / Management Ability to abduct “will never get better” It is NOT possible to create “normal” eye mvts via

surgery Treat any underlying amblyopia; Check for hearing deficits if indicated Indications for surgery: head turns (to try to gain ortho

and fusion) or big tropia in primary Resist the urge to resect (tighten) the affected muscle:

will increase retraction and the muscle doesn’t work well anyway. Some have even proposed weakening the affected LR more to decrease retraction

Usually begin with MR recession; can do transpositions of SR and IR to LR with concurrent MR recession

Möbius Syndrome 6th and 7th nerve palsies BUT…

Motility is more than just limited abduction; may be some limited adduction as well (sometimes partial 3rd)as well as some elevation defects

Mask-like facies may be incomplete (may spare lower face

Check for incomplete lid closure, corneal anesthesia, and exposure

Accompanied by limb, chest, tongue problems Agenesis/dysgenesis of limbs; terminal limb problems

like polydactyly or syndactyly Check for absent pectoralis muscle (Poland’s Anomaly) Tongue hypoplastic; dental malocclusion

Möbius Syndrome Postmortem evidence shows cause is agenesis of

6th, 7th, and 12th cranial nerve nuclei (the EOMs themselves are normal…though may become fibrotic from lack of innervation)

Ophtho Management medial rectus recession for abduction deficits Lubricate corneas if not good lid closure; lateral

tarsorrhaphy to protect corneas if needed Referral for speech eval, cardiac eval, and

endocrine eval (can have heart and endocrine problems too)

Usually only 10% mentally delayed Most are rejected and depressed due to facial

appearance

Möbius Syndrome

Brown’s Syndrome Unable to elevate the adducted eye

Restricted on forced duction testing Cause: developmental anomaly of the SO tendon

(the trochlea and the SO tendon derive from the same mesenchymal tissue; in utero, these get tangled up and cause tethering / restriction of SO tendon

Usually congenital, but can be acquired Trauma or surgery to canthal area, inflammation, or

metastasis to area DDx: IO underaction and SO overaction

These do not have positive forced ductions 10% are bilateral Sometimes runs in families (always bilateral)

Brown’s Syndrome Kids present with abnormal head posture, or parents

saying “eyes just don’t move right when pt looks up at me” Usually will note EXOtropia in upgaze Treat for significant head posture or significant

hypotropia / diplopia in primary, loss of stereo Options: none good: SO weakening via SO tenectomy

(but can over-do, and cause SO paresis); silicone expander (fallen out of favor); most need at least 2 re-ops

Leave these kids alone unless forced to do something: reported tendency toward improvement as child get older, as abnormal connections between the trochlea and SO break down; but not always: some adults still have it;

Brown’s Syndrome

Thyroid Eye Disease Restrictive myopathy with lymphocytic infiltration of

EOMs Usual order for boards IMSLow (IR affected

most>MR>SR>LR; from recent lecture by Dr. Gearity, the 3 muscles are affected about the same.

Usual misalignment is proptosis, hypotropia, and esotropia (from scarred/fibrosed IR pulling eye down; fibrosed MR pulling eye in); forced ductions are usually positive

Present with diplopia that does not follow any pattern, therefore prisms usually don’t work

Thyroid Eye Disease Most are hyperthyroid at dx, but can be euthyroid or

hypothyroid Get TSI, TSH, and T4 (per Dr. Gearity) CT orbits can be helpful to see degree of EOM

involvement Thyroid eye disease often co-exists with myasthenia so

eval for this also If optic nerve involved, may need orbital decompression

prior to strabismus surgery Surgery: optional oral prednisone for 2 weeks (“to soften

things up”); then surgery (ie inferior rectus recession: aim to undercorrect

Thyroid Eye Disease

Congenital Fibrosis Syndromes

Group of congenital anomalies with variable amts of restriction of EOMs via replacement of muscle tissue with fibrous tissue

Can be single muscle on one eye to all muscles on both eyes

Often levator involved=>ptosis=>chin up head posture DDx is PEO (frozen eyes and ptosis) Many types inherited (auto dominant usually) though

can be sporadic Etiology unknown Goal: get ortho in primary

Congenital Fibrosis Syndromes

General fibrosis of all the EOMs (mostly auto dominant inheritance)

Congenital fibrosis of the IR=>cannot look up; can mimic double elevator palsy

Congenital fibrosis of the MR/LR (strabismus fixus) Can present with congenital esotropia appearance

with both eyes pointing down and in toward nose Congenital fibrosis of the SR=>pt cannot look

down

Congenital Fibrosis - familial

Chronic Progressive External Ophthalmoplegia (CPEO)

Presents as ptosis, followed by progressive paresis of EOMs; pupils spared

DDX is Congenital Fibrosis (frozen eye and ptosis) Triad of PEO, pigmentary retina changes and heart

block/cardio problems is Kearns-Sayre, (usually before age 20) (many times a board question); mgmt: refer for sequential EKG Other signs of K-S: short stature, hearing loss,

diabetes/endocrine problems Dx: EOM or limb muscle bx show “ragged red fibers”

(actually are clumps of degenerated mitochondria) on trichrome stain

May be mitochondrial dysfunction as cause

MyastheniaLook for variable strabismus throughout

the day or on sequential examsDiplopia is often intermittentCan be “ocular “ only or systemic Look for fatigueability on extended

upgazeOften reversed by a few minutes of cold

ice in a rubber glove on the eyelids

Myasthenia Refer to Neuro for Tensilon test / EMG

Test dose 0.1cc edrophonium (tensilon) If ok, then 0.9cc edrophonium Keep IV atropine on hand as antidote

Can test for Acetylcholine receptor antibody

Found in 90% of acquired MG (not found in congenital MG); only present 50% of time in “ocular” MG

Antistriated muscle antibody Found in 90% of MG with thymoma and 30% of MG pts without

thymoma

Therefore, in typical diplopia pt with fatigueability, but no systemic sx, these tests will be negative often despite disease, so still refer to neuro for tensilon test if suspicious

Internuclear Ophthalmoplegia (INO)

Looks like a “one-sided MR palsy” (ipsilateral to the lesion), with the other eye having horizontal nystagmus

The limited adduction may be total or partial Both eyes adduct normally on convergence to a

near target Is a problem in the MLF (medial longitudinal

fasciculus) of the brain stem Interruption in signal from from abducens relay

signals from reaching the contralateral oculomotor nucleus, impairing adduction

INOAnatomy

IF I WANT TO LOOK LEFT:Left PPRF stimulates the Left 6th N

nucleus=> (abduct left eye)Left 6th N nucleus stimulates the MLFMLF crosses and ascends to the

contralateral (right) 3rd nucleusTo give contralateral (right) MR

contraction (adduct right eye)

INO In adults: Multiple Sclerosis is common

cause and many times is bilateral INO In kids: posterior fossa tumors (eg

brainstem glioma), Arnold-Chiari, head trauma, sickle cell

In old folks: frontal lobe CVA or tumor

One and a Half Syndrome(INO + )(Fisher’s Syndrome)

Injury to the PPRF (also known as the lateral gaze center) or the 6th nerve nucleus causes loss of ipsi abduction and contralateral adduction) (the one)

Injury to the ipsi MLF (knocks off ipsi adduction) (the half)

The only mvt remaining is the contralateral abduction (via the contralateral 6th N nucleus

DDx: congenital fibrosis (forced ductions give the answer)

Congenital Oculomotor Apraxia (Saccade Initiation Failure)

These folks cannot voluntarily initiate horizontal eye mvts => see head thrusting to look to sides

Vertical mvts intactGet MRI to look for head tumors If acquired oculomotor apraxia in adult,

look for parietal CVA, mets, or traumaEtiology unknown

3rd, 4th, and 6th Nerve PalsiesCongenital/Acquired

Survey of 160 palsies in kids 50+% were 6th N palsies 25% were 3rd N palsies 25% were 4th or multiple N palsies

Trauma most common cause in kids

3rd Nerve Palsies Congenital

Rare Look for ptosis and exotropia (with mixture of strab

due to reduced adduction, elevation, and depression) and pupil involvement (the eye is down and out due to unopposed LR and SO (a depressor)

Pupil usually dilated Look for aberrant regeneration due to misdirection

of any 3rd N fibers that actually are working

3rd N Palsies Acquired (kids)

Trauma (most common cause of acquired 3rd N Post-viral Infectious (13/147 cases of meningitis had 3rd N palsies;

Hflu, Nmeningitidis, Spneumoniae) Inflammatory Migraine (ophthalmoplegic migraine)

Pain around the eye for 24-48 hrs, with N/V, then as pain lessens, a 3rd N palsy develops, can last for a few days to a few months

Recurrent, usually a family h/o migraine First attack usually before age 12 More common in boys than girls

Tumor (eg brainstem glioma)

3rd N PalsiesAcquired (adults)

Aneurysm (youngest age for PCOM aneurysm is 14 so far); “angiography to exclude an aneurysm is NOT justified below the age of 10” (Taylors text)

Diabetes (usually resolves over 6 months) Trauma Infection Tumor

3rd Nerve Palsy Ptosis, exotropia and

hypotropia (only the LR and SO working…so eye is down and out) and blown pupil

4th Nerve Palsy Congenital

Look for the head tilt; do measurements with head straight, to show the strabismus

Ddx of head tilt, with hypertropia in primary gaze is IOOA, DVD, Duane’s with upshoot

Bielschowsky: LRL: means LHT, worse on right gaze, worse on L head tilt (is L SO4 palsy) (not to be confused with LLL which is RIO palsy)

Look for excyclotorsion Look for facial asymmetry (hypodevelopment/ thinner face on

contralateral side) Many times these present later in life; looking at old photos

shows the head tilt present in childhood and they have large fusional amplitudes

Causes: frequently birth trauma or just bad anatomy (weak SO tendon)

4th N Palsy Acquired

Note: since the 4th N has the longest course and is the only one to exit on the dorsal surface of the brain stem, so it the most vulnerable to damage from trauma

Causes: Trauma (#1) Diabetes / ischemia (#2) Hydrocephalus / Tumors Post infectious Demyelinating disease Commonly: No cause found

Surgical Mgmt of SO4 palsy: IO myectomy +/- SO tuck +/- additional vertical rectus surgery

Oblique Palsies and Overactions - TORSION

1st photo shows normal relationship of fovea to disk with respect to torsion. Normal fovea location is between two imaginary lines drawn thru middle of disk and lower margin of disk (direct view)

Inferior oblique overaction / SO palsy could show the right fundus above; [note that on your 20Diopter INDIRECT view, the fovea should be at upper half of disk, and torsion will make fovea seem way up, as you view it with indirect]

6th Nerve PalsyCongenital

Duane’s Transient LR palsy of Newborns, usually

goes away before it is even diagnosed (may be as common as 1/ 182 normal births); sometimes there is h/o birth trauma or forceps

6th N Palsy Acquired

Trauma (40%) Neoplasms (16%) (pontine glioma) Intracranial Hypertension (Pseudotumor or

hydrocephalus) Infection (meningitis, varicella, Lyme) and s/p

vaccination (MMR) Acquired 6th N palsy of unknown cause in children:

isolated, painless 6th N palsy that resolves in 8-12 weeks; w/u negative (including MRI and CSF and neuro w/u); may recur

6th Nerve Palsy

6th Nerve palsy in a 10yo male who had a brainstem glioma

3rd/4th/5thv1v2/6th combo palsy Image the cavernous sinus area If there is proptosis, consider an orbital

apex syndrome