1. Surgical management of partially accommodative ET with convergence excess DR ELINA LANDA OCULAR MOTILITY RVEEH JOURNAL CLUB EDITED BY LIONEL KOWAL

2. Convergence excess ET – ET with D/N disparity, where the near angle exceeds the distance by more than 10∆( with or without high AC/A ratio)
Surgical goals:
1 Alleviate symptoms
2 Reduce N deviation without altering D
3 Improve binocularity
4 Eliminate need for bifocals
Group A
Group B
D- ortho or microtropia
N- ET
Good chance for binocularity
and high grades of stereo
D- ET
Chance for binocularity low or absent

3. M. M. Parks
BMR is the best surgery resulting in AC/A ratio improvement by 66%
Standard surgery for partially accom ET was based on residual deviation for dist with full correction. 50%- rate of undercorrections
Parks suggested (1975) to add 1mm to each MR rc in pts with conv excess ET :
- significant undercorrection rate
- no success in eliminating the bifocals (1/3 with bf)

4. Augmented BMR by Kushner
Augmented rc- BMR+1mm if N-D 10∆ BMR+1.5mm ∆ max 6.5mm
BMR+2.0mm ∆
“Comparison augmented BMR with BMR & faden”
Outcomes:- alignment follow up 5 years
- bifocals
- spectacles
Result Augmented BMR
BMR+ faden
Alignment %
Bifocals %
Spectacles /25
80%
57%
5/21

5. Kushner: Augmented BMR 15y outcome
22/25 were available
86% good alignment:
27% alignment +correction for alignment
36% with correction for VA
23% w/o correction
3/22 unsatisfactory results:
1/3- recurrent ET
2/3 XT

6. Augmented BMR by Wright for ET with high hypermetropia
Standard
Augmented
74% alignment + full correction
26%
undercorrections
88%
Alignment
12%
XT + full correction
Overcorrections were treated by reduction of “+”
Pt: Dsc 40ET; Nsc 50E Dcc 20ET; Ncc 30ET
Standard Dsc+Dcc/2 25pd
Augmented Nsc+Ncc/ pd
Refr b/w +3 to +9
Conv excess 10/30 SG
12/40 AG

7. Kushner: should you overcorrect and cut the plus?
22 pts with consec XT
8/ /22
Low High +
Low - < + 2.5D
High - > + 2.5D
High AC/A
88% %
Low High+
Results
Low +
High+
Alignment
Gross stereo(800)
Good stereo<200
Reoperations
88%
75%
63%
13%
30%
14% 7%
29%

8. Augmented BMR using the Prism Adaptation Test
The preoperative use of prisms to determine the max angle and estimate fusional potential
60% - prism responders
50% - St BMR % Aug BMR
Alignment within 8pd
79% % nonresp %
Long-term (3y) results (Rosenbaum)
Alignment
76% PA sx vs % non PA sx

9. PAT in convergence excess ET
Kutschke -65 pts with conv excess ET
31 sx for near PAT for dist PAT
95% alignment % alignment
0 – need in bf /3 – bf
Overcorrection – 9%

10. PAT in convergence excess ET
Kraft – pts
83% responders % non- responders
72% align.+fusion % align. + fusion
76% alignment % alignment
Unsuccessful pts
9 undercorrections overcorrections

11. Strabismus surgery for elimination of bifocals
16pts
13/16 PAT /16 PAT-
10/13 – 1 surgery /13 – 1 surgery
2/13 cons XT /13 – cons XT
1/13 rec ET
Surgery is based on PAT for near angle

12. Faden operation
Aim of faden is to weaken the EOM only in its field of action, not affecting ocular alignment in primary gaze
Peterseim and Buckly : 95%- norm. AC/A
70% - good motor and sensory fusion for near
Vivian : 95% success in decrease of near deviation and stereo

13. main mechanism - mechanical restriction of movement through the pulley
Posterior fixation sutures- permanent suturing of muscle belly to sclera near the equator
A. Scott (The fadenoperation: mechanical effects. Am Orthopt J 1977) suggested a mechanical explanation:
-moving the effective insertion to the equator results in torque reduction ( b/c of shortening of muscle’s lever arm for rotation of the globe)
J Demer (Posterior fixation sutures: a revised mechanical explanation… Am J Ophthal 1999): suggested an explanation based on rectus muscle pulleys:
main mechanism - mechanical restriction of movement through the pulley

14. Modifications to the fadenoperation
Intraoperative forced duction test
Minimize the amount of sharp dissection
The optimum position of the suture may be at the most posterior extent of the blunt dissection exposing the EOM

15. Medial rectus pulley posterior fixation is as effective as scleral posterior fixation for acquired ET with high AC/A R A. Clark, J L. Demer Am J Ophthalmol 2004
9 pts : standard BMR posterior fixation surgery with scleral sutures:
2 – only scleral faden – BMRc + scleral faden
Postoperatively:
6/9 – imroved stereoacuity
8/9 – no longer needed bifocals
 D/N disparity average of 12∆
13 pts : BMR  pulley posterior fixation:
3 – only pulley posterior fixation
10 – BMR +pulley post fixation
Postoperatively:
8/13 – improved stereoacuity
12/13 – no longer needed bifocals
 D/N disparity average of 14∆

16. 3 recent pulley suture patients Patient 1
5yo
Dcc 30pd; Ncc 50pd
Refr RT +2.5D ; Lt +3.0D
Sx: BMR 5.5 (Parks) + pulley post fix
1mo postop: Dcc 6pd; Ncc 12pd

17. Patient 2 14yo. Swimming pool ET L only. +4 DS OU Dsc 35pd Nsc 40
Dcc 6pd Ncc 16pd
Sx: Lt MR pulley
1mo after Dsc 20pd Nsc 20pd

18. Patient 3 5yo Dcc 25pd; Ncc 45pd LET; Lt amblyopia 6/36
Refr: RT +4.5D Lt +5.5D
Sx: BMR 5mm (for 35pd) + pulley post. fix.
1week postop.: Dcc 12pd; Ncc 14pd