Highlighting the causes, symptoms, diagnosis of congenital and acquired, unilateral and bilateral SO palsy, muscle sequelae and complications. Includes simplified understanding of Park three step test.

1. DIAGNOSIS AND
MANAGEMENT OF
SUPERIOR OBLIQUE PALSY
-DR.STUTI SOMANI AGARWAL

2. • Most common isolated cranial nerve palsy in strabismic patients.
• Traditionally classified as Congenital and Acquired.
• Treatment is based on deviation and not on aetiology.

3. CAUSES OF SO PALSY:
CONGENITAL
1. Laxity of the tendon (redundant tendon)
2. Abnormally long tendon.
3. Misdirected tendon
4. Absent tendon
5. Posterior insertion into tenon’s and not sclera
The tendon anomaly is secondary to denervation or a
primary anatomical defect is debatable.
MRI REPORTS have suggested volume reduction in
congenital SO palsy cases but not so in acquired cases.
ACQUIRED
1. Trauma
2. Idiopathic
3. Tumour
4. Inflammation
5. Infection
6. Aneurysm
7. Iatrogenic: neuro sx, sinus sx, orbital sx
Acquired cases have normal tendon
• Sudden onset SO palsy without h/o trauma, in most instances is decompensated congenital SO palsy.*
• MG and MS may present with isolated SO palsy of insidious onset, mimicking congenital case.*
* Von Noorden

4. SYMPTOMS OF SO PALSY:
• Asthenopia.
• Patients c/o diplopia- vertical, torsional, diagonal.
• Cervical discomfort due to AHP.
• AHP: Head tilt to opposite side, face turn to same side and chin down in V pattern esotropias.
• Facial asymmetry: midfacial hypoplasia on the side of tilt.
• **Paradoxical head tilt.
• Diplopia MC in acquired cases, but reported in upto 25% congenital cases.
• Image tilting with Vertical diplopia occurs only in acquired cases.
• SO MUSCLE CAUSES DEPRESSION, INTORSION, ABDUCTION OF THE EYE.
• THUS ITS PARALYSIS CAUSES HYPERTROPIA, EXCYCLOTORSION, V PATTERN ESOTROPIA
( esp B/L SO palsy cases)

5. MUSCLE ACTION:
• Depression : Greatest in adduction
• Incyclotorsion: Greater in down gaze and abduction
• Abduction: Primarily in down gaze
• Diagnosis of SO palsy is by the presence of hypertropia, which is greatest in the nasal field of the
involved eye, but not necessarily in the direction of the paralysed muscle.
• Hypertropia is due to unopposed overaction of its antagonist, IO, greatest in adduction.
• Due to spread of comitance, with secondary contracture of I/L SR, the hypertropia may involve the
entire lower field of gaze. This can be easily seen on FDT.
• There may be associated pseudo-overaction of C/L SO, due to secondary deviation.

6. Knapp’s and Moore introduced a classification
describing the most common manifestations,
depending upon the magnitude of hypertropia in
the diagnostic position of gaze.
7 classes are distinguished.

7. DIAGNOSIS:
1. PARK THREE STEP TEST: based on the Bielchowsky head tilt phenomenon.
STEP 1: identifying the hypertropic eye:
thus, it’s the paresis of the SO and IR of the hypertropic eye or the IO and SR of hypotropic eye
STEP2: hypertropia increasing on lateral gazes:
obliques have greater action in adduction and vertical recti in abduction,
thus right hypertropia increasing in right gaze points to Right IR or left SO;
and Right hypertropia increasing in left gaze is due to either Right SO or left SR.
STEP 3: hypertropia increasing in which head tilt:
to remember superiors are intortors and inferiors are extortors,
the eye on the side of tilt has intorsion and the other extorsion,
hence right hypertropia increasing in right head tilt points to right superiors and left inferiors.
Now at the end we will conclude upon the single cyclovertical muscle which is paralysed

8. STEP 1
STEP 2
STEP 3
WOOG
BOOT

9. 2. TORSION- subjective methods: double maddox rod test, synaptophore, hess charting
objective method: fundus examination and photographs.
• Congenital cases usually have no/ minimal torsion.
• Acquired cases have measurable degree of torsion.
• B/L cases have > 10 degrees of excyclotorsion.
3. VERSION- gives an idea of the overaction and underactions of the diff muscles.
I/L SO Underaction, I/L IO overaction and C/L SO “apparent” overaction.
4. Neuroimaging in acquired cases- brainstem lesions –INO, Horner’s, Parinaud syndrome, ataxia.
Isolated u/l so palsy: aneurysm of Sup cerebellar art and ICA

10. UNILATERAL SO PALSY
• Incomitant hypertropia, usually greatest in the
nasal field of the eye with the paralysis;
• Underaction of the involved superior oblique
muscle and/or overaction of its antagonistic
inferior oblique muscle; and
• Increase of hypertropia tilting the head toward
the paralyzed side (positive Bielschowsky's test)
BILATERAL SO PALSY
• Right hypertropia in left gaze and left hypertropia
in right gaze
• A positive Bielschowsky test to both shoulders
• Underaction of both superior oblique muscles
and/or overaction of both inferior oblique muscles
• Chin down
• V pattern esotropia> 15PD
• Objective extorsion >10degrees
• h/o Head trauma

11. MUSCLE SEQUELAE IN SO PALSY:
• UNDERACTON OF I/L SO
• OVERACTION OF C/L SYNERGIST - C/L IR
• OVERACTION OF I/L DIRECT ANTAGONIST – I/L IO
• UNDERACTION OF ANTAGONIST OF C/L SYNERGIST- C/L SR (inhibitional palsy)

12. MANAGEMENT
• PRE-OP MEASUREMENTS OF THE DEVIATION IN ALL GAZES.
• MEASUREMENT IN OBLIQUE FIELDS HELP IN DIAGNOSIS OF MASKED B/L SO PALSY
• INTRAOP: FDT TO LOOK FOR RESTRICTIVE AND PARALYTIC MUSCLES.
• EXAGERRATED FDT FOR LAXITY OF THE TENDON. PICTURE

14. SURGICAL PROCEDURES :
• OPTIONS AVAILABLE:
1. I/L IO WEAKENING: MYECTOMY,
DISINSERTION
GRADED RECESSION
ANT. TRANSPOSITION
2. I/L SO TUCK
3. C/L IR RECESSION
4. I/L SR RECESSION IN CASES OF CONTRACTURE

15. UNILATERAL
SO PALSY
TRACTION
TEST
ABSENT
TENDON
MODERATE
LAXITY
EVERYTHING ELSE,
ACQUIRED U/L CASES
1. IO WEAKENING
2. SR RECESSION
I/L SIDE
1. SO TUCK
2. IO WEAKENING
I/L SIDE
AMOUNT OF HYPERTROPIA
<15 PD > 15 PD
1. IO OVERACTION-
IO WEAKENING
2. SR
CONTRACTURE:
I/L SR
RECESSION
3. NO SR
CONTRACTURE:
C/L IR
RECESSION
I/L IO WEAKENIG
COMBINED WITH
1. I/L SR RECESSION
2. I/L SO TUCK
3. C/L IR RECESSION

16. BILATERAL
SO PALSY
HARADA-ITO MODIFIED HARADA-ITO
SPLITTING OF SO AND
ADVANCING THE
ANTERIOR FIBRES ONLY
ADVANCING THE NT FIBRES OF SO
UPTO THE SUPERIOR BORDER OF
LR, ABOUT 8MM POST TO THE
INSERTION OF LR
• COMBINING THESE WITH C/L IR RECESSION
• IF RESIDUAL TORSIONAL DIPLOPIA PERSISTS, NASAL TRANSPOSITION OF ONE OR BOTH IR
• IF EXCYCLOTORSION<10PD, HARA ITO IS NOT PERFORMED
• FOR V-PATTERN ESO AND DIPLOPIA ON SIDE GAZES, IO WEAKENING ON 1/BOTH SIDES WITH IR RECESSION B/L

17. COMPLICATIONS:
• Overcorrection causes diplopia in opposite gaze due the fusional vergence
amplitude developed in the direction of pre-op deviation
• Brown’s syndrome, diplopia in upgaze esp dur to so tuck procedure.

18. DIFFERNTIAL DIAGNOSIS:
1. SKEW DEVIATION- sudden acquired hyperdeviation with other neurologic signs, with no
measurable torsion.
2. THYROID REATED OPHTHALMOPATHY- IR is most commonly affected.
3. BROWN’S SYNDROME- I/L IO underaction.
4. PRIMARY IO OVERACTION- absence of primary position hypertropia, negative Bielchowsy
head tilt, lack of torsion.
5. PSEUDOPARALYSIS-plagiocephaly, due to retroplacement of the trochlea.

19. SALIENT POINTS:
1. IO myectomy has a greater reduction in PP hypertropia >15pd , whereas, disinsertion of IO
was effective in <15pd. *
• Myectomy is irreversible and chances of bleeding are more; not so with disinsertion.
*Akbari MR, Sadeghi AM, Ghadimi H, Nikdel M. Outcome of inferior oblique disinsertion versus myectomy in the surgical
treatment of unilateral congenital superior oblique palsy. Journal of American Association for Pediatric Ophthalmology and
Strabismus. 2019 Mar 15.

20. 2. Single muscle sx with IO weakening is effective for upto 15pd deviations, two muscle sx are
preferred for larger deviations.
- 2muscle sx can be IO weakening and SO tuck.**
- 2muscle sx can be IO weakening and IR recession.***
** Saunders RA. Treatment of superior oblique palsy with superior oblique tendon tuck and inferior oblique
muscle myectomy. Ophthalmology. 1986 Aug 1;93(8):1023-7.
** *Hatz KB, Brodsky MC, Killer HE. When is isolated inferior oblique muscle surgery an appropriate
treatment for superior oblique palsy?. European journal of ophthalmology. 2006 Jan;16(1):10-6.

21. 3. SO tuck procedures have excellent surgical outcome wrt decreasing angle of deviation,
diplopia but has r/o acquired brown’s syndrome.***
4. Even in long standing congenital SO palsy cases with moderate to large angle deviation, IO
weakening is better than IO weakening with SO tuck due to risk of overcorrection and brown’s
syndrome.
5. SR recession combined with IO weakening in cases of SR contracture works well.
***Dwivedi R, Marsh IB. Superior oblique tuck: evaluation of surgical outcomes. Strabismus. 2019 Jan
2;27(1):24-9.

22. THANK YOU