Botulinum toxin or Botox is a neurotoxin of a protein nature, being an exotoxin of bacterial origin, which acts at the neuronal level, by blocking the impulses transmitted through nerves from the brain to the muscles.
In small quantities, the dosage of which is now standardized, the injection of the toxin into various muscles is a successful therapy for various eye diseases such as strabismus, nystagmus, blepharospasm and of course is used with great success in cosmetic treatments of the oculo-eyelid area.
In general, the effect of the toxin is transient, but because the extraocular muscles adapt permanently and the brain resets the impulses it sends to the muscles, it is sometimes possible that the results are very good and definitive after a minimum number of injections.
Botulinum toxin is considered an alternative to strabismus surgery in certain clinical situations.
The indications for toxin injection for strabismus are as follows:
- when the patient refuses surgery to correct strabismus
- when the patient suffers from newly installed double vision provided that it is not due to autoimmune diseases or neuromuscular dystrophies
- in recent paralysis of the extraocular muscles after head or orbit injuries
- when the patient has a clear contraindication for general anaesthesia or surgery
- in the case of small squint deviations resulting from other squint interventions
- when the patient has a high risk of diplopia (double vision) after surgery and we want to simulate the postoperative effect to allow the patient to gradually adapt to the new situation
- in recent years, it is successfully used in infantile convergent strabismus (infantile esotropia) but the opinions of specialists differ
- as an additional, intraoperative treatment, to enhance the effect of surgery
- other situations in which the doctor considers that the patient may be favoured by the use of the toxin
It is contraindicated in patients with neuromuscular disorders, certain autoimmune diseases, in multiple allergic patients, especially those with albumin allergies.
Of course, the doctor will determine after a thorough history whether the patient can benefit from this treatment or not.
Not all patients respond the same and sometimes the injection is very difficult due to the patient’s conformation or the scars resulting from previous operations.
In case of strabismus or nystagmus, the injection procedure is simple and is performed either with the help of an electromyograph that signals the moment when the needle reached the muscle or by direct injection, after visualizing the targeted muscle, through a small incision. The manoeuvre is performed after prior anaesthesia of the conjunctiva with anaesthetic in the form of drops and gel. If necessary, the patient can be easily sedated, in case of adults.
It is not painful and lasts a few minutes.
In children, the procedure is performed under general anaesthesia.
The most experienced clinic in pediatric ophthalmology and strabismus in Romania
The effect of the toxin begins to set in approximately 1-3 days after the injection, with the maximum effect occurring 3 weeks after the injection. In most situations it remains constant for 5-6 months but the effect may be shorter or longer, depending on the dosage, the condition and the response of the body, especially of the brain to the new situation.
The use of botulinum toxin in strabismus dates back to the 1980s and was introduced by American physician Alan Scott. Oftapro has been using it successfully in the clinic since 2008, with a large number of patients responding very well to this type of treatment. The only side effects reported were transient deviation of the eye to the opposite side and eyelid ptosis (also transient).