Diagnosis and Management of

Superior Oblique Palsy

Pediatric Ophthalmology

LSU Medical Center

Shreveport

Superior Oblique Palsy

Most common cause of:Congenital Vertical DeviationAcquired Vertical Deviation

Anatomy: Superior Oblique

Function: Superior Oblique

Functions of Superior Oblique

DepressionGreatest in adduction

IncyclotorsionGreater in down gaze and abduction

AbductionPrimarily in down gaze

SO Palsy Results In:

HypertropiaGreater in adduction

ExcyclotorsionGreater in down gaze and abduction

EsotropiaPrimarily in down gaze “V” patternPrimarily in bilateral SO palsy

Causes of SO Palsy

Congenital or childhood onset Head tilt may appear by age 2-4 months

May cause facial asymmetry

Deviation may not be noted until adulthood

Acquired Closed head trauma (most) Vascular disease Neoplasm Inflammation (e.g. temporal arteritis)

Systemic Workup of SO Palsy

Usually unrewarding if SO palsy isolated (i.e., no other new ocular or neurologic signs or symptoms)

Definitely not needed if signs of childhood onset present

Evolution of New SO Palsy

Initially:Vertical deviation greatest in field of SO

(i.e., gaze down and in)Later

Contracture of antagonist and changes in other vertical muscles often occurs

Vertical deviation often greater in other fields of gaze

Spread of Comitance in SO Palsy

Knapp’s Classification of SO Palsy

Torsional Diplopia in SO Palsy

Eye itself is extortedVisible on fundus exam

Superior pole of image seen by patient appears intorted

If normal eye is occluded and patient asked to hold object straight, he will hold it in an extorted position

Fundus Torsion

Fundus TorsionIndirect

Ophthalmoscope View

Diplopia in SO Palsy

Diplopia may be vertical, torsional and/or horizontal

Occasionally, torsional diplopia occurs with little or no vertical deviation

Bilateral SO palsy: large amount of torsional diplopia, no vertical deviation in primary if bilateral palsy symmetric

Signs and Symptoms of SO Palsy

Diplopia

Torticollis

Strabismus

Torticollis in SO Palsy

Classical:Head tilt to normal sideFace turn to normal sideChin down

Not stereotyped: variations existHead tilt may be “paradoxical”: i.e. to side

of paretic eye

Torticollis In SO Palsy

Torticollis may be large and noted at age 2-4 months of age

Head tilt may be small and not noted by patientOld pictures (or spouse) helpful

Torticollis in SO Palsy

Torticollis in SO Palsy

Facial Asymmetry in SO Palsy

Ocular Rotations in SO Palsy

Over 50%: no overt weakness of SOEye appears to move down and in normally

May look like palsy of contralateral SR (if patient fixates with paretic eye in adduction, non paretic eye will be hypotropic)Called inhibitional palsy of contralateral

antagonist of Chavasse

Park’s Three Step Test for Diagnosis of SO

PalsyOften needed since diagnosis often not clear from versions and ductions

Often cannot localize weak muscle from rotations (ductions and versions)

Step One

Cover test in primary gaze

Determine if RHT or LHT present in primary gaze

E.g. RHT would mean either:Weak right depressor: RIR or RSO, orWeak left elevator: LSR or LIO

Park’s Three Step Test

Provides reliable information only if an isolated palsy of a cyclovertical muscle is presentNot helpful in other conditions, such as:DVDThyroid eye diseaseBrown’s syndromeBlowout fracture with entrapped IR

Park’s Three Step Test:Step Two

Perform cover testing in right and left gaze

Determine if HT greater in right or left gaze

E.g., RHT worse in left gaze: Indicates weak RSO or weak LSR Deviation greater when optical axis aligns with

angle of muscle from origin to insertion

Park’s Three Step TestStep Three

Step three is Bielschowsky head tilt test

Measure deviation in right head tilt and left head tilt

Determine if deviation greater in right head tilt or left head tilt

Head Tilt Test

If a superior muscle is weak, HT greater on tilt toward involved muscle

If an inferior muscle is weak, HT greater on head tilt opposite involved side

Head Tilt with No Muscle Palsy

Head Tilt in RSO Palsy

SIN: Superior Muscles Intort

Superior Oblique and Superior Rectus are both intorters

Inferior Oblique and Inferior Rectus are both extorters

Head Tilt Test

After step one and step two in Park’s three step test, one is always left with two muscles Either two superior muscles or

Two inferior muscles

E.g., RSO or LSR LSO or RSR LIO or RIR RIO or LIR

Head Tilt Test

Step Three:

E.g., RHT worse on left gaze After two steps, means either weak RSO

or weak LSRHT worse on right head tilt: RSO palsyHT worse on left head tilt: LSR palsy

SO Palsy: Chart to Memorize

Hypertropia

Gaze where HT larger

Head Tilt where HT larger

RSO Palsy

R L R

LSO Palsy

L R L

Other Ways to Diagnose SO Palsy

Red lens or Red Maddox rod over one eye Red lens: fixate on a letter Maddox rod: fixate on a bright light

Measure subjectively in: Right and left gaze Right and left head tilt

Very helpful for small acquired deviations

Bilateral SO Palsy

V pattern with esotropia in downgaze commonExcylotorsion over 10-15 degreesHT changes from right to left gazeE.g., RHT on left gaze, LHT on right gaze

Type of HT changes on head tiltE.g., RHT on right head tilt, LHT on left

head tilt

Bilateral SO Palsy

Vertical deviation often asymmetric If symmetric, little or no vertical in primary gaze

Often first diagnosed after surgery for apparent unilateral SO palsy (called “masked bilateral SO palsy”)

Double Maddox Rod helpful to diagnose pre-operatively

Measurement of Torsion

Double Maddox rod placed in trial frame One red, one white (or two red Maddox rods)

Patient views a single white light source

Patient sees a red line and a white line

Rotate one lens to make the two lines parallel (subjectively)

Use vertical prism if needed to separate lines

Double Maddox Rod to Measure Torsion

Treatment of SO Palsy

Surgical Treatment

Non-Surgical Treatment

Non Surgical Treatment of SO Palsy

Wait six months if new palsy occurs Many improve spontaneously

Patch for diplopia Let adult choose which eye to patch, usually non

paretic eye

Prisms May be helpful in adults with diplopia and with

smaller less incomitant deviations

Amblyopia Treat if present May occur in either eye

Indications for Surgery

StrabismusNoticeable or bothersome to patient

Head tiltNoticeable or bothersome to patient

Diplopia

Which Muscle to Operate On

Measure vertical deviation in all fields

Pay particular attention to:Primary gazeRight and left gazeOblique gazes opposite palsy

Important Fields of Gaze

Surgery for SO Palsy

Surgery planned primarily based on the deviation and where the deviation is largest

Head Tilt primarily useful for diagnosis

Presence of bilateral SO palsy will change treatment plan

Surgical Treatment of SO Palsy

Some patients, mostly childhood onset types, have laxity in the SO tendonFound with forced duction of SO under

general anesthesia

Patients with laxity of SO tendon need SO surgery (generally SO tuck) to equalize forced duction with normal SO

Surgical Treatment of SO Palsy

Superior Oblique tuck performed on patient without laxity in the tendon likely to cause a “Brown syndrome”, or inability to look upward in adduction

SO tuck still often indicated in:SO palsy worse in straight down gazeBilateral SO Palsy

Bishop Tendon Tucker

Surgical Treatment of SO Palsy

Patients without laxity of SO, primary surgical procedure is weakening (generally recession) of IO, the direct antagonist to the weak SO

Unilateral cases IO weakening done in 50-80% of casesCan be done with adjustable suture

Surgical Treatment of SO Palsy

If deviation greatest in field of SO and no tendon laxity present, choices are:Weaken opposite inferior rectusTuck SO

Which muscle depends on difference of deviation in primary and lateral gaze,and down and down and lateral gaze

Surgical Treatment of SO Palsy

Recess ipsilateral superior rectus if:Positive forced duction on attempted

depression of paretic eyeFive diopter or more vertical in abduction of

paretic eye

How Many Muscles to Operate on

Determine deviation in field of greatest deviationIf that deviation is under 15-20 diopters, operate on one muscleIf that deviation is over 15-20 diopters, operate on two musclesThree muscles: usually results in overcorrection

IO Weakening

Amount of correction varies with amount of overaction of IO

Can correct 10-15 diopters in primary gaze

Can be done as adjustable suture in adults

Treatment of Bilateral SO Palsy

Mostly torsional with little vertical deviation: Harada Ito procedure

With large HT in side gaze: tuck SO OU

Usually bilateral IO overaction not seen

SO Tuck: Dangers

Can easily overcorrect and create restriction if SO tendon is not lax

In the past, large percentage of SO tucks had to be “taken down”

Use forced ductions at surgery as guide to amount of tuck

Other Surgical Complications

IO weakening Can cause “ adherence syndrome” if fat pad

penetrated: will look like IO overaction on other side (restriction of elevation in abduction of operated eye)

IR Recession Can easily cause lower eyelid retraction Can prevent eyelid retraction with recession of lower lid

retractors

Amount of Surgery

IO weakeningRecess to just posterior and lateral to IR

insertionCan do asymmetric IO recession OU

SO tuckDetermine at surgeryUsually 6-14 mm, sometimes more

Amount of Surgery

IR RecessionUsually 3-5 mm: use adjustable suture in

adults

SR RecessionUsually 3-5 mm: use adjustable sutures in

adults

Work Up of SO Palsy

HistoryTraumaDiplopiaTorticollisOther neurological signs or symptoms

Work Up of SO Palsy

Observe torticollis

Measurement in all cardinal fields and head tilt right and left

Double Maddox Rod to measure torsion

Observe fundus for torsion

SO Palsy with Torsion and No Or Minimal HT

Tuck or advance anterior portion of SO tendon

Advancement of anterior SO called Harada Ito procedure

Harada Ito Procedure

Canine Tooth Syndrome

Trauma to SO tendon

Results in SO palsy with poor elevation in adduction (“ Brown’s syndrome”)

Rx: difficultFree restrictionsWeaken yoke IR

Canine Tooth Syndrome

Types of SO PalsyChildhood Onset

Adult Onset

Size of deviation

Large Small

Fusional Vergence

Large Small

Bilaterality Almost never 25%

Diplopia Rare Always

Usual Rx Weaken IO, +/- SO tuck

Recess IR

Course of SO Palsy

May present early in childhood with torticollis or strabismus

May present later ( often age 30-50) with symptoms from strabismus or torticollis

Field of Single Vision

Very important to patient

Often ignored by physician

Measure pre-op and post-op ( can use Goldman perimeter) or estimate

Warn patients that deviation will probably be present in some fields post-op