Botulinum toxin injections into the extraocular muscles for strabismus in adults

Botulinum toxin injections, which have proven themselves in the field of anti-age, can also be effective for strabismus.

If for some reason surgery is not possible, or if the patient prefers a less invasive procedure, injecting botulinum toxin into the external eye muscles can be an excellent alternative.

In this article estet-portal.com Ophthalmic Surgeon Joanne Hancox ( Joanne Hancox) describes the use of botulinum toxin type A (BoNT-A) for the treatment of strabismus in adult patients.

What is strabismus, types and causes of strabismus

• When Botulinum Toxin Injections Are Effective for Strabismus
• Treatment of strabismus with botulinum toxin type A: mechanism of action and results
• What complications can occur after injections of botulinum toxin into extraocular muscles
• s What is strabismus, types and causes of strabismus

Strabism or strabismus

– this is a condition in which one or both eyes, when looking straight ahead, deviate from the central axis.

Squint is diagnosed in about 4% of the adult population. There is a common misconception among patients that it is impossible to solve this problem in adulthood.

Depending on

the direction of deviation

, the following

types of strabismus

: Horizontal:

1. Converging (esotropia) – turning the eye inward; Divergent (exotropy) – turning the eye outward.
   Vertical:
2. Hypertropia – eye shift up; Hypotropia – downward shift of the eye.
   Rotary
   – torsion strabismus.
3. There is a common misconception among patients that it is impossible to get rid of strabismus in adulthood.
The degree of asymmetry is affected by eye movements and the direction of gaze.

muscle diseases;

cranial nerve palsy;

• eye injury;
• Holo injury
• you.
• When are botulinum toxin injections effective for strabismus

Surgery

remains by far the most commonly used and effective treatment for strabismus, with long lasting results.

In case of technical difficulties or impossibility to perform the operation, as well as at the request of the patient, it is possible to resort to a less invasive botulinum therapy procedure that does not disturb the usual rhythm of life.

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! Scientific literature has reported successful botulinum toxin injections for adult strabismus in cases of:

defects that are the result of childhood strabismus, secondary or residual abnormalities;

eye misalignment due to poor vision – sensory or secondary abnormalities;

• paralysis of III, IV and V pairs of cranial nerves;
• strabismus after ophthalmic surgery;
• congenital strabismus (Dwayne's syndrome);
• small angle deflection;
• complex pathologies (progressive external ophthalmoplegia, Graves' ophthalmopathy, myasthenia gravis
• is).
• Treatment of strabismus with botulinum toxin type A: mechanism of action and results
As with other muscles,

the mechanism of action

of botulinum toxin injections for strabismus is to

block the neuromuscular junctions

of the target extraocular muscle. But much lower doses of the drug – total 1–5 units, depending on the specific case.

Read also: The possibilities of botulinum toxin injections for the correction of aesthetic defects of the nose

Complete paralysis of the target muscle is not the ultimate goal in the treatment of strabismus, as this is fraught with impaired eye movement. Desired effect – weakening of the target muscle until normal alignment of the eyes is restored without disturbing their mobility.

The effect after injections of botulinum toxin

is manifested by the weakening of the treated extraocular muscle only a couple of days after the procedure.

The peak result is observed 2 weeks after botulinum therapy, and over the next 3-4 months, the effect gradually weakens. In some patients, the results of botulinum toxin correction last longer.

Introduction of

BoNT

-A into extraocular muscles in case of strabismus – a procedure that requires special training of the ophthalmic surgeon, since during the injection the muscles are not visualized, and too deep injection of the drug can provoke permanent loss of vision. In order to reduce the risk, injections are performed under the control of electromyography.

During the preparation phase, the surface of the eye is treated with anesthetic drops.

Botulinum toxin is administered using a syringe with a needle-electrode connected to an electromyograph. First, the patient is asked to look away, and then – towards the target muscle. During movement of the target muscle,

electromyograph signal

is heard, which indicates that the needle is in the muscle.

To minimize the risk of complications, the drug is administered at the time of maximum machine signal.

Two weeks after the procedure, patients return for a re-examination, during which they determine the need for repeated injections if the effect in the treatment of strabismus was not sufficiently pronounced after the initial injection.

Methods to increase the duration and effectiveness of botulinum toxin action

Following visits are planned in 3-4 months after therapy.

There is no limit to the number of adequately spaced botulinum toxin injections for strabismus. According to the results of studies, with long-term use of BoNT-A, the average angle of strabismus decreases significantly over time and the frequency of required injections decreases accordingly

.

What complications can occur after botulinum toxin injections into extraocular muscles Potential

complications

of botulinum toxin injections into extraocular muscles include: ptosis due to diffusion of the toxin into the muscle that lifts the upper eyelid, or unwanted deviations of the eyeball due to spread of the drug to other extraocular muscles.

To reduce the risk of these complications, the doctor does not remove the needle from the injection site for 30 seconds after the toxin injection.

Botulinum toxin: a terrible poison or an invaluable medicine

Hemorrhage (subconjunctival hemorrhage) may appear on the surface of the eye or bruising in the periorbital region – these phenomena are temporary. The risk of perforation of the eyeball when correcting strabismus with botulinum toxin is quite low – this complication occurs in about 1 in 10,000 cases.

According to

magazine Aesthetics

.

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