WHICH OPERATION FOR ESOTROPIA? EVIDENCE- BASED RECOMMENDATIONS SOME RECOMMENDATIONS HAVE LOTS OF EVIDENCE OTHERS HAVE LESS LIONEL KOWAL RANZCO 2008

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

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

BMR Reliability of surgical tables Over range ∆ 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

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

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

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

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

How far can a medial rectus safely be recessed? J Pediatr Ophthalmol Strabismus Kushner BJ… J Pediatr Ophthalmol Strabismus.Kushner 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]

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  age 12 mo doesn’t grow ‘perfectly’ over next y 3. Scar b/w MR & sclera stretches

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

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

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

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

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

60 ∆ BMR u Botox for one MR 70 ∆ …each MR

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

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

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