WHICH OPERATION FOR ESOTROPIA? EVIDENCE- BASED RECOMMENDATIONS SOME RECOMMENDATIONS HAVE LOTS OF EVIDENCE OTHERS HAVE L

1. WHICH OPERATION FOR ESOTROPIA?EVIDENCE- BASED RECOMMENDATIONSSOME RECOMMENDATIONS HAVE LOTS OF EVIDENCEOTHERS HAVE LESS LIONEL KOWAL RANZCO 2008

2. BMR vs. Rc-Rs • If D = N & ≤ 35∆ : little / no difference • If N > D [high AC/A, convergence Xs,..] most [inc. many Rc-Rs enthusiasts] will do BMR (usually augmented in some way) • Densely amblyopic ET N>D: Augment the MR Rc part of Rc-Rs with Faden or pulley suture

3. What happens when MR is recessed in ET? New position of globe : rotates f/w in the orbit Reduced torque : less chance of recurrent ET No LR Rs • LR: As globe rotates forward, LR insertion rotates posteriorly in orbit & LR now has some slack. Takes up slack quickly. 1-2w to see final effect LR Rs • LR tension matches MR tension Slight LR tension in next 2-4w..to see final effect

4. BMR Reliability of surgical tables • Over range 15 - 50 ∆ In month 2: orthotropia achieved in ~80% of cases with poor / no motor fusion & >> 80% with some/ good motor fusion [‘capture range’] • PAT study: sensory fusion postop [and preop with ∆] larger factor in alignment outcome than surgical dose

5. BMR Fudging the tables • Parks: augment BMR dose in conv Xs Parks: Distance mm + 1mm OU Most: Usual tables for near angle

6. BMR Fudging the tables for + Wright: augment BMR dose for low+ in hope of reducing spectacle dependence • ≥ +3 : no fudging for + • ~+2: add 0.5mm to one muscle, not the tighter one. Any consec XT should be lessened by uncorrected + • +1: do not increase BMR dose. No + to soak up any consec XT

7. Fudging for big / small globes • >24mm: add 10% to dose • <20mm: cut 10%

8. BMR Fudging the tables • Roth: reduce MR dose for a tight muscle

9. How far can a medial rectus safely be recessed? • J Pediatr Ophthalmol Strabismus. 1994Kushner BJ… • .. MR Rc up to 1.5 mm posterior to equator should not produce postoperative MR underaction ..[and] .. overcorrection • MR Rc > 1.5 mm posterior to equator may do so. • Need K’s, axial length and a table • LK: 6.5 mm [AL <20: 6mm]

10. Long term consec XT after BMR • Infants straightened <12 mo age: ~1% p.a. rate of consecutive XT Reasons • 1. Over-recessed or surgical mishap • 2. New post- surgery geometric relationship that  orthotropia @ age 12 mo doesn’t grow ‘perfectly’ over next 10 - 20y • 3. Scar b/w MR & sclera stretches

11. Rc - Rs • No tables for > 35∆ Possibly less consec XT • Any tendency to scar stretching will apply to both LR & MR Acquired vertical • 2° to inadvertent inf obl capture

12. Rc - Rs c.f. BMR Refractive effects: • More temporary astigmatism 20+% Might make amblyopia worse Lid changes • More noticeable if involves one eye than with small symmetric changes of BMR

13. Up to 35∆ • BMR or Rc-Rs? • Do the procedure you do better

14. 35 - 50 ∆ BMR • 35 ∆: 5mm • 50 ∆: 6mm In between, can do • 40 ∆: 5 / 5.5 • 45 ∆: 5.5 / 6 LK: Smaller dose on the tighter MR

15. 60 ∆ • BMR 6mm for 50 ∆ • Each MR 6mm: 25 ∆ • BLR resect 5 mm: 20 ∆ • Each LR resect 5 mm: 10 ∆ • 60 ∆: BMR 6mm plus one LR resect 5mm

16. 60 ∆ • BMR 6 • 2.5 u Botox for one MR • 70 ∆ • …each MR

17. One medial rectus • Up to 4mm : for ~10 ∆ • Little experience • LK worries about lateral incomitance

18. ET : D>NDivergence Xs Options • Prism adaptation to see if will augment for N with view to doing BMR or • Rc-Rs or LR Rs OU

19. Numerous other variables • Personal surgical technique esp. Rs • Generic “Vicryl” • Scar formation …………… Thank you!