Botulinum A Toxin Injection for Blepharospasm and Hemifacial Spasm

This information aims to provide patients with information about the benefits and side-effects of Botulinum A Toxin injection for blepharospasm and hemifacial spasm.

What is Blepharospasm?

Blepharospasm is a condition that affects the muscles of the eyelid and brow. The symptoms include increased blinking and involuntary closure of the eyelids which cannot be controlled by the patient.

The underlying cause of the condition is unknown, although some find that stress makes it worse.

What is Hemifacial Spasm?

Hemifacial (literally ‘half the face’) spasm is a similar condition, which affects usually just one side of the face, causing spasms lasting from a few seconds to several minutes.

The muscles of the face are all controlled by the facial nerve. If something presses on the nerve somewhere along its course (i.e. unusual blood vessels) it can affect how the signals are carried to the face. This may cause muscles to twitch (or contract), or to go into the spasm, when you don’t want them to.

These conditions can be helped with the use of Botulinum A Toxin injection into the affected muscles.

What is Botulinum A Toxin?

Botulinum toxin is a chemical produced by a bacterium called Clostridium Botulinum which in large amounts is toxic. However, small doses of botulinum toxin can be used to selectively weaken the muscles causing the spasm.

How does the Botulinum A Toxin work?

By blocking the release of acetylcholine at the neuromuscular junction, the toxin weakens some of the muscles that close the eyes or cause spasm.  This decreases the frequency of blinking and the uncontrollable spasm. The aim is to enable the patient to return to a more normal life.

How long does it take to work and how long does it last?

The injections start to work after 24 to 72 hours, having maximum effect by 2 to 3 weeks. The effect of the injections last for 8 to 12 weeks and repeated injections are necessary for continued relief.

Who will perform my procedure?

The initial assessment and injections will be performed in the Eye Clinic, by the consultant, to establish the effective dose for each individual. If the patient is happy with the result, the subsequent injections may be given by a trained nurse practitioner.

What happens during the procedure?

During the procedure you will be awake.  A needle will be placed into the affected muscle. When the needle is in the correct place, a small amount of botulin toxin will be injected.

What are the side effects and risks of this treatment?

There are some risks as with all procedures. It is normal to feel some discomfort during and for a while after the injections. Small bruises occasionally develop but settle quickly.

Sometimes other muscles may be affected, resulting in a droopy eyelid or double vision. Blurred vision and watering eyes may occur.

If this happens it will resolve, as the effect of the injections wear off.

Information and support:

The Dystonia Society

2nd Floor 89 Albert Embankment


Helpline: 020 7793 3650                 Office: 020 7793 3651

Email: [email protected]


Northern Blepharospasm Dystonia Society Group

Based in Leeds, Yorkshire

Contact: Jane Hewertson               Telephone: 0845 899 7101

Email: [email protected]

(American) Benign Essential Blepharospasm Research Foundation

PO Box 12468

Beaumont, TX 77726-2468, USA

Telephone:  (409) 832-0788                      Fax: (409) 832-0890

Email: [email protected]


Telephone numbers

Clinic 8, Lincoln County Hospital              01522 307180

These are not emergency numbers. If you have an emergency, please contact your GP.