This document discusses the functional use of botulinum toxin type A in neuro-ophthalmology. It focuses on benign essential blepharospasm (BEB) and hemifacial spasm. For BEB, botulinum toxin injection into the orbicularis oculi and corrugator muscles is an effective treatment with minimal side effects. For hemifacial spasm, botulinum toxin can provide relief of symptoms but microvascular decompression surgery may be needed for long-term management. Careful injection technique and minimizing doses can help reduce adverse effects.

1. Functional use of Botulinum
toxin A in Neuro-Ophthalmology
Busaba Sathornsumetee MD.
Mettapracharak Hospital
31 August 2012

2. Benign Essential
Blepharospasm

3. BEB
• Idiopathic focal dystonia
• Involuntary intermittent bilateral eyelid closure
• Women are affected more than men
• Usually begins in the 4th -6th decade of life

4. Involved muscles
• Orbicularis oculi
• Corrugator
• Procerus

5. Etiology
• Unknown
• No underlying causes
• Parkinson disease, lower pontine lesion

6. Symptoms
• Increased blinking (early)
• Difficulty in eyelid opening (early)
• Squeezing of the eyelids
• Photophobia, eye pain, dry eyes
• Functional blindness
• Disturb daily activity, cosmetic

7. Signs

8. Differential diagnosis
• Reflex blepharospasm
• Eyelid myokymia
• Early Hemifacial spasm
• Apraxia of eyelid opening

9. Meige syndrome
• BEB (often precede)
• Oromandibular dystonia
- Dystonia of lower face, jaw, neck

10. Management
• Conservative treatment
• Oral medication
• Botulinum toxin injection
• Myectomy

11. Botulinum toxin A for BEB
(FDA approved 1989)
(FDA approved 1989)
• Advise Risk & Benefit
• No contraindication for Botulinum toxin A injection
Neuromuscular disorder, Pregnancy-Lactation, Drug interaction
• May stop ASA 7 days (cosmetic issue)
• Cold pack for 5-10 mins (relieve pain & stop bleeding)

12. Potential adverse effects
• Effect of the toxin on adjacent non-target muscles
• Injection technique
• Mild & transient effects

13. Potential adverse effects
• Ptosis (7-11%)
• Lagophthalmos (5-12%)
• Symptomatic dry eyes
• Diplopia (<1%)
• Ecchymosis
• Lower facial weakness

14. Site of injection for BEB
- Orbicularis oculi (pretarsal part)
* subcutaneous injection
* medial & lateral area
* 2.5-5.0 unit (upper)
* 5.0-10.0 unit (lower)
- Corrugator & Procerus
* intramuscular injection
* 2.5-5.0 unit

15. Failure of botulinum toxin
• Inability of botulinum toxin to relieve squeezing
• Problem of eyelid opening
- Apraxia of eyelid opening (50%)
- Dermatochalasis, Brow ptosis

16. Apraxia of eyelid opening
• Inability to raise upper eyelid
• Often occur with BEB
• No eyelid squeezing , Elevation of eyebrow
• Botulinum toxin + upper myectomy + tightening levator M.

17. Hemifacial spasm

18. Hemifacial spasm
• Unilateral
• Dystonia of facial muscles
- Orbicularis oculi (precedes)
- Zygomaticus major
- Risorius
- Mentalis
• Normal ocular surface , Persist while sleeping

19. Hemifacial spasm
• The whole face on one side contracts
• Eyelid closure
• Elevation of corner of mouth

20. Etiology
• Hyperexcitability of the facial motor nucleus
- Idiopathic
- Ischemia or mass in pons (1%)
• Compression of the facial nerve near its exit from the
brainstem
- Tortuous AICA
- Dolichoectatic artery of the posterior circulation

22. Approach HFS
• History taking
Dizziness, vertigo, ataxia, facial numbness, hearing loss
Diplopia, facial palsy
• Examination
EOM, CN 5- 7- 8

23. Neuroimaging
• Brain MRI (เน้น brainstem) + MRA with/without GAD
• ตามตำาราแนะนำาให้ส่งทุก case
• ใน clinical practice จริงๆ มีหลากหลาย
- บางที่ส่งทุก case
- เลือกส่งในบาง case
มี neurological deficits อืนร่วม ไม่ตอบสนองต่อการรักษา
่

24. Management HFS
• Oral medications (same as for BEB)
• Chemodenervation with Botulinum toxin A
Duration of action tends to be longer than in BEB
• Microvascular decompression (craniotomy)

25. Microvascular decompression

26. Site for injection
• Orbicularis Oculi +/- Corrugator
• Zygomaticus Major (2.5-7.5 U)
• Risorius (some cases, 2.5 U)
• Mentalis (2.5-5 U)
(Intramuscular injection for lower face)
• ไม่แนะนำาให้ฉดบริเวณ Orbicularis Oris
ี

27. Potential adverse effects
• Same as BEB
• Asymmetric smile
• Drooping of the cheek and angle of mouth

28. How to decrease the adverse
effect ?
• Small dosage for Zygomaticus Major
• Avoid Orbicularis Oris
• Inject Botulinum toxin at Depressor Anguli Oris
(DAO) or contralateral Zygomaticus major
• Lower dose if secondary to facial palsy

29. Take home message
• BEB is often a chronic progressive condition
• Beware of other causes of treatment failure with botulinum toxin
• Keep brain MRI in mind for HFS
• Counselling is important before treatment

30. Thank you