Complicated Adult Strabismus

Michael JonesMBBS PhD FRANZCO

•Is adult strabismus surgery purely “cosmetic”?

•Strabismus is an abnormal motor and sensory state and any realignment is actually “restorative” or “reconstructive” surgery

Adult Strabismus

Indications for surgery

• RESTORATION OF BINOCULAR SINGLE VISION

• DIPLOPIA

• INCOMITANT STRABISMUS

• ASTHENOPIA

• ASYMPTOMATIC PATIENTS

• COMPENSATORY HEAD POSTURE

• NYSTAGMUS

• EXPANSION OF THE FIELD OF VISION IN PATIENTS WITH ESOTROPIA

• PSYCHOSOCIAL AND VOCATIONAL INDICATIONS

Eye Muscle Surgery

• The strabismus procedure is now individualised for each patient in terms of muscle choice and surgical dose

• It is no longer acceptable to simply plan correction for the primary position alignment

• Attempt to maximise the field of BSV (field of fusion), ideally within 30 degrees from the primary position

Incomitant Strabismus

• Yoke muscle surgery on the fellow eye

• If paresis or mechanical restriction weaken the yoked contralateral muscle by recession

• Can use an adjustable suture to titrate the degree of duction limitation to match that of the limited yoke muscle

• Retroequatorial posterior fixation suture (“fadenoperation”) on the yoke muscle

• Rather than place intrascleral sutures retroequatorially on the same muscle, the surgeon can fix the rectus muscle belly directly to the pulley

• Can also be used in convergence excess esotropia in children

Paralytic Strabismus

• Complete third or sixth nerve palsies are not correctable with traditional recess-resect procedures, even if supramaximal

• The resected muscle does not function and the tightening effect “unwinds” over time

Paralytic Strabismus

• Vertical rectus muscle transposition to the LR insertion

• Jensen or Hummelshein procedure

• The MR must be weakened by recession

• Foster modification

• Retroequatorial myopexy sutures to redirect the vertical muscles into a horizontal configuration above and below the LR

• Does not require concurrent weakening of the medial rectus unless there is unexpected undercorrection after primary transposition

Duane syndrome• Recognition that Duanne syndrome is a spectrum of

innervational anomalies

• Grouped with congenital cranial dissinervation disorders

• CFEOM

• Mobius syndrome

• Congenital CN 4 palsy

• Congenital CN 3 palsy

Duane syndrome• Common feature of globe retraction on

adduction to co-innervation of LR and MR on attempted adduction

• Neuroanatomic studies showing hypoplasia of the sixth nerve and its nucleus, with miswiring of of the third nerve to LR

• EMG and dynamic MRI studies show anomalous LR contraction on adduction

Duane syndrome• Analyse any given case according to 5 clinical

features:

• Presence of compensatory head posture

• The type of heterotropia in primary position (if eyes not straight)

• The presence of upshoots and/or downshoots on adduction of the eye (innervational or mechanical)

• The severity of retraction on adduction

• Whether the syndrome is unilateral or bilateral

Duane syndrome

• Transposition of the vertical rectus muscles with or without deactivation of the lateral rectus

• Surgery on the fellow eye in unilateral cases is sometimes necessary to optimise results

• Rarely, a small resection of LR can be used to treat some forms of Duane syndrome with esotropia

• Simple recession

Thank you