STEPHANIE WEST CONSULTANT OPHTHALMIC SURGEON
Specialist squint, double vision and children’s eye care in Southampton
Botulinum Toxin (BOTOX®) for Adult Squint
A precise, minimally invasive treatment that can improve eye alignment, reduce double vision and help plan future squint surgery.
Botulinum toxin is injected directly into a selected eye muscle to weaken it temporarily. It can be used as treatment in its own right, while a nerve palsy recovers, or as a valuable diagnostic test before surgery.
Did you know? BOTOX® was first developed for squint
Many people associate BOTOX® with wrinkle treatment, but its medical story began in ophthalmology. In the late 1970s, American ophthalmologist Dr Alan B. Scott developed tiny, targeted injections of purified botulinum toxin to weaken overactive eye muscles and improve eye alignment.
Botulinum toxin was first approved in 1989 for strabismus (squint) and blepharospasm. Its cosmetic effect on facial lines was noticed later, and cosmetic use followed afterwards.
1970s
Dr Alan Scott develops targeted botulinum toxin injections for eye-muscle disorders.
1989
Approved for strabismus and blepharospasm.
Later
Reduction in facial wrinkles is noticed during medical treatment.
Today
Used in ophthalmology, neurology and cosmetic medicine worldwide.
BOTOX® is not simply a cosmetic treatment.
It was pioneered by ophthalmologists for squint and has been used around the eyes for more than four decades.
Why might Botox be recommended?
Botulinum toxin is not suitable for every squint. It is most useful when a temporary, reversible change in muscle strength could improve symptoms or provide information that helps guide treatment.
Reduce double vision
It may improve diplopia caused by a recent or established eye misalignment.
Allow time for recovery
It can provide temporary alignment while a nerve palsy is given time to recover.
Help plan surgery
A temporary change can show whether improved alignment is likely to be comfortable or beneficial.
Treat a residual squint
It may help selected undercorrections, overcorrections or recurrent squints after previous surgery.
Alternative to surgery
It can be useful when surgery is unsuitable, not desired or best deferred.
Prevent muscle tightening
In selected acute nerve palsies, early treatment may reduce secondary muscle contracture.
How does botulinum toxin work?
Botulinum toxin temporarily blocks the signal between a nerve and the injected eye muscle. The muscle becomes weaker, allowing the opposing muscle to move the eye into a different position.
The effect usually begins after 2–3 days, is strongest after approximately 1–2 weeks, and gradually wears off over several weeks or months. In some people, the improved alignment lasts longer because the eye muscles and visual system adapt to the new position.
1. Target muscle selected
The muscle responsible for the unwanted pull is identified.
2. Muscle temporarily weakens
The toxin reduces the nerve signal reaching that muscle.
3. Eye position changes
The opposing muscle can pull the eye into a more favourable position.
4. Effect gradually fades
Muscle strength returns as the nerve endings recover.
What happens during the procedure?
The injection is usually performed in a minor procedure room with you lying comfortably on a couch. The complete appointment commonly takes around 30 minutes, although the injection itself is brief.
1. Anaesthetic drops
Drops numb the surface of the eye and reduce discomfort.
2. Electrodes are positioned
Small electrodes may be placed on the forehead to help identify muscle activity.
3. Fine needle placement
A very fine needle passes through the conjunctiva into the selected eye muscle.
4. Move the eye towards the needle
You are asked to look in the direction that activates the target muscle. The electrical signal helps confirm the needle is correctly positioned.
5. Injection
A very small dose of botulinum toxin is delivered into the muscle.
6. Needle held briefly
The needle is kept still for around 30 seconds to reduce unwanted spread before it is removed.
Afterwards: an antibiotic drop may be given. You should arrange for someone to accompany you home and you should not drive after the procedure.
Potential benefits
No general anaesthetic
The procedure is normally carried out using anaesthetic eye drops.
No stitches
There is no surgical incision or muscle suture.
Quick recovery
Most people go home shortly after treatment.
Reversible effect
The muscle weakness usually reduces gradually with time.
May avoid surgery
Some selected squints can be managed without an operation.
Useful diagnostic information
The response can guide future surgical planning.
Possible side effects and complications
Before treatment, the expected benefits and risks will be discussed in relation to your particular squint and general health.
Common temporary effects
- Temporary drooping of the upper eyelid (ptosis)
- Temporary change or reversal in the direction of the squint
- Temporary new or altered double vision
- Initial overcorrection or undercorrection
- Redness or a small bruise on the white of the eye
- Bruising around the eyelids
- A mild ache or discomfort around the eye
These effects are usually temporary and improve as the toxin wears off.
Rare complications
- Scratch or minor injury to the cornea
- Significant bleeding around the eye
- Very rare penetration of the eye by the needle
- Very rare permanent weakness of the injected muscle
- Allergic reaction
- Little or no improvement despite treatment
Serious complications are uncommon. The treatment does not cause botulism or food poisoning when used in these tiny, targeted medical doses.
Frequently asked questions
Anaesthetic drops are used first. Most patients describe pressure, a brief sharp sensation or mild discomfort rather than significant pain.
No. Your vision may be blurred and the alignment of your eyes may change. Please arrange for someone to accompany you home, and do not drive while experiencing double vision.
The effect commonly starts after 2–3 days and is usually strongest after 1–2 weeks.
The effect normally lasts from several weeks to a few months. Some patients retain a longer-lasting improvement.
Some patients have one injection only. Others may benefit from repeat treatment, depending on the response and the underlying cause of the squint.
Yes. Botulinum toxin may be used instead of surgery, while waiting for recovery, or as part of planning future squint surgery.
Trademark notice: BOTOX® is a registered trademark of Allergan, an AbbVie company. On this page, “botulinum toxin” is used as the general medical term for this type of treatment.
Could botulinum toxin be an option for your squint?
Every squint is different. A detailed assessment can determine whether botulinum toxin, prism glasses, observation or surgery is most appropriate for you.