2. Duane ’ s retraction syndrome Core problem – LR has double innervation 3rd nerve & 6th nerve  MR & LR co-fire on aDduction - determines retraction Clinical presentation depends on: - how aberrant is LR innervation [% of 3rd vs. % of 6th] - How tight the MR / LR become

3. Clinical presentation depends on balance of abnormal innervation to LR LR innervation 3 N 6N 30% 70% ET – less Some retraction on ADduction LR innervation 3N 6N 70% 30% ET more More retraction on ADduction ABduction restricted LR innervation tight MR ‘chronic ET’ ADduction restricted tight LR

4. Usual pattern: “ Type 1 ” restricted ABduction some ET some retraction Face turn Unilateral patterns: -Exodeviation (restricted ADduction) with or without up& downshoot -Relatively immobile globe in PP with marked retraction, up& downshoot -Simultaneous abduction of each eye Bilateral patterns -Bilateral DS with fusion -Bilateral DS without fusion marked ET marked XT Limitation of ABduction ET retraction on ADduction

5. TREATMENT Traditional: ipsi MR recession. No long term follow up Strabismus specialists rarely do this  iatrogenic “Type 3” Usual surgery: contralateral MR Rc, or transposition of SR & IR Up & downshoot ipsi LR Rc & split Severe retraction LR fixation to periosteum & SR - IR transposition