duanes retraction syndrome

Question 1

what is duanes retraction syndrome

Answer 1

a condition where the eyes are unable to move fully in the horizontal (side to side) direction

Question 2

aetiology of duanes

Answer 2

innervation of lateral rectus by extra branches of the IIIN in place of absent or deficient VIN fibres.
· Autospsy findings of absent 6th Nucleus and Nerve
· Inferior Division of the 3rd was found to supply the Lateral Rectus

• Usually sporadic but can be familial
• Disruption to embryogenic development in weeks 4-10 thought to be responsible
• This would account for the incidence of other skeletal, auricular and neural defects associated

Question 3

hebers classification of duanes

Answer 3

Type 1 – Lim ABDUCTION
* Widening of Palp Aperture on attempted abduction
* Due to Lack of innervation to LR
* Narrowing of Palpebral Aperture on ADD + Globe Retraction
* Due to maximum innervation reaching the LR when the eye is adducted ( Co-contracture of MR+LR by 3rd N)

Type 2 – Lim ADDUCTION
* Co-contraction of the horizontal recti on attempted adduction

Type 3 – Lim both ABDUCTION + ADDUCTION

Only get globe retraction on adduction - only check globe retraction from above

Question 4

ocular clinical features of duanes

Answer 4

• Limited horizontal motility
  
  • Unilateral or Bilateral
  • AHP – face turn to affected side
  • Mostly esodeviation and usually esophoria
  • Normal BSV
  • Up and Down shoots on adduction
  • A+V patterns
  • Globe retraction on ADDUCTION
  • Narrowing of palp fissure on ADD
  • Widening of palp fissure on attempted ABD
  • Diplopia is rare

Question 5

other clinical features of duanes

Answer 5

• 30% of patients with DRS have developmental abnormalities
  
  • Eye, Ear, Kidney, Heart and other limbs
  • Coloboma, Ptosis, Epibulbar dermoid cysts

Goldenhar Syndrome
Klippel-Feil syndrome - REMEMBER THESE TWO

Question 6

Typical motility of duanes

Answer 6

Limitation of Right ABDUCTION \

Overaction of Contralateral MR (Synergist)

Upshoot RE on ADDUCTION

Globe retraction on ADDUCTION

Narrowing of palp fissure on Adduction

Widening on ABDUCTION

Question 7

management of duanes

Answer 7

Refer to HES routine
Often no treatment required due to BSV in PP, small angle with suppression, CHP
Amblyopia therapy, if required

Surgery – decompensation ONLY

• cosmetically poor CHP
  ccosmetically poor deviation in PP
• severe globe retraction with or without upshoots and downshoots