Treatment with Botulinum toxin

Patient Experience

  • Reference Number: HEY1134/2020
  • Departments: Ophthalmology Department
  • Last Updated: 30 June 2020


This leaflet has been produced to give you general information about your procedure.  Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and the healthcare team, but may act as a starting point for discussion.   If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team.

What is Botulinum toxin?

Botulinum toxin often referred to by its shortened name “Botox®” is a drug which causes muscles to relax.  It is naturally produced by a type of bacteria called Clostridium botulinum.  It is now manufactured for use as an established treatment for a number of medical conditions.

How does Botulinum toxin work?

Muscles contract when they receive signal from a nerve. Botulinum toxin stops the nerve-endings from transmitting these signals (Fig 1).  When botulinum toxin is injected, it spreads throughout the tissue into the nerve endings. This means the muscle receives less signal from the nerve causing the muscle to relax.   Botulinum toxin can therefore be used to help in conditions which are caused by overacting muscles.

What conditions are Botulinum toxin used to treat?

Botulinum toxin is commonly used to treat the following conditions:


Blepharospasm is a condition caused by abnormal contraction of the muscles around the eye.  This causes involuntary blinking or even full closure of the eyelids.  It can affect one side, but in most cases it affects both eyes.  Doctors do not know the exact cause of blepharospasm but it may be caused by loss of control of the natural blink reflex.  Blepharospasm often follows a particular pattern and might be worse at different times of day.  It can be triggered by things such as bright light, stress or tiredness. In its severe form blepharospasm can last several minutes and make the patient blind due to the inability to open their eyelids.

Hemifacial spasm

Hemifacial spasm is very similar to blepharospasm.  It causes spasm around the eye but usually only affecting one side.  It often involves other muscles further down the face on the same side, for example those around the cheek and mouth.  More is understood about the causes of hemifacial spasm.  The facial nerve controls facial movement.  Some patients are found to have a blood vessel in the brain which sits too closely to the facial nerve and intermittently touches it, resulting in spasms.   Another cause is facial paralysis.  When it recovers this can happen abnormally, resulting in hemifacial spasm.

Treatment for other eye conditions

Botulinum toxin can be used to make the upper eyelid droop down; this is called a “ptosis”.  There are a number of conditions where this can actually be helpful:The cornea:  the cornea is the clear window at the front of the eye. If there is a problem with the cornea, injecting Botulinum toxin to make the eyelid upper eyelid droop down and cover it for some time can help it to heal. Thyroid eye disease: sometimes in thyroid eye disease the upper eyelid can sit a little higher than usual causing a startled or “staring” appearance.  A small amount of Botulinum toxin can be injected to cause the upper eyelid to sit slightly lower.

Are there any other or alternative treatments for blepharospasm and hemifacial spasm?

There are measures you can take to reduce the frequency of spasms.  For example, if you find a trigger is bright sunlight, make sure you always have your sunglasses to hand.  Sometimes dry eyes can trigger or worsen the frequency of the spasms. Using a moisturising eye drop regularly can help with this.  If you suffer particularly when tired, ensure when you can that you are well rested.  Sometimes people find that patching one eye if it is particularly troublesome can stop the contractions temporarily.

The first line treatment for blepharospasm and hemifacial spasm is botulinum toxin injection which is sufficient for most patients.

Sometimes patients become resistant to treatment or only have a partial response.  Over time if you have lots of botulinum toxin injections, it may not work as well as it used to.  In this case there are various medications which are usually prescribed by a neurology doctor to help with spasms.  However these do have a range of side effects.

How do I prepare for the procedure?

Please read the information leaflet. Share the information it contains with your partner and family (if you wish) so that they can be of help and support. There may be information they need to know, especially if they are taking care of you following this procedure.

Points to note:

  • The procedure is carried out in the eye outpatient department.
  • For this procedure you should not drive to and from the appointment.
  • You should take all your regular medications.

What will happen?

Where to go on arrival

You should arrive at the outpatient clinic within the Eye Hospital on our Hull Royal Infirmary site and report directly to reception.

The procedure

You will be required to sign a consent form.  This leaflet is designed to answer the majority of queries, but please ask your doctor any additional questions you may have.

Tiny amounts of Botulinum toxin are injected into the muscles around the eye that need treatment.  This varies from person to person but usually involves between 2 and 6 injections per side (see Fig 2).  This takes a few minutes.  Most people find the injections are a little uncomfortable but manage well.

What should I expect afterwards?

You will start to notice an effect of the treatment between 3 to 5 days.  The full effect takes 2 weeks to develop.   If you had your injection for blepharospasm or hemifacial spasm you should notice the amount of spasm slowly becoming less and that it is easier to keep the eye open when you want.  The effect of Botulinum toxin typically lasts 3 months, but can start to wear off at this time.  To keep a long lasting effect, injections usually need to be repeated every 3 to 4 months.

Even using the exactly the same injection dose and sites the effect between procedures can vary slightly.  You may notice a difference between the result on one side of the face compared to the other or one procedure may seem to work more or less than the last.   This is because there are lots of factors which interact to affect how the Botulinum toxin works. It is very rare, but some patients develop resistance to treatment, meaning it becomes less effective.

Are there any side effects or risks of Botulinum toxin injection?

Risk of the injection

The most common side effects are a direct result of the injection.  The following may occur at the injection site:

  • Bleeding or bruising, or redness
  • Discomfort, pain or tenderness
  • A small amount of swelling
  • Itchiness
  • Tingling or numbness
  • Less commonly, infection may occur.  This causes noticeable swelling, redness and pain around the sites of injection.

Effects on the eye

Sometimes the eye itself can feel a bit irritated, dry, watery or sensitive to light after the procedure.  It is less common for people to report a problem with their vision.

Other side effects occur when the Botulinum toxin works too well or because it naturally spreads it may have an effect on other muscles around the eye.  If this happens it can cause:

  • Drooping of the upper eyelid, if the muscle holding the eyelid up is affected
  • Being unable to close the eyelids fully.  This can cause a dry eye, discomfort or blurred vision.  It is very rare to have a more serious problem with the cornea, the clear window at the front of the eye.
  • Double vision
  • A change in the eyelid position – the lower eyelid may turn out or inwards

If you suffer these effects they will only last as long as the botulinum toxin works, which is around 3 months.

Much less commonly injections around the eye can cause problems moving the muscles of the face; this is called facial paresis and is a rare complication of Botulinum toxin injection.

General Effects

Botulinum toxin very rarely causes generalised side effects, far from the site of injection. This may include feeling generally unwell, flu-like or having a headache. These effects should usually disappear within a few days.

Although rare, you should seek medical advice urgently if you notice any problems with swallowing, speaking or breathing after treatment.

Is there anyone who should not receive botulinum toxin injections?

  • Anyone who has a known allergy to botulinum toxin.
  • You are pregnant or breastfeeding or planning on becoming pregnant.
  • Individuals who have an active infection in any of the areas to be injected should not undergo the procedure.  The infection should be treated appropriately and the appointment re-scheduled.
  • People with muscular disorders such as myasthenia gravis should not receive treatment as they are at high risk of suffering more dangerous side effects.

Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Ophthalmic Department on (01482) 608788 or Ward 35 (Eye Hospital) on (01482) 604346.

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

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