Botulinum Toxin for Strabismus Treatment

The bacterial species Clostridium botulinum produces a class of neurotoxins known as botulinum toxin. At the neuromuscular junction, botulinum toxin A prevents acetylcholine from being released. Following a Botox intramuscular injection, the injected EOM becomes paralysed 2-4 days after the injection and remains so clinically for at least 5-8 weeks. Muscle function recovery takes five to fourteen weeks, depending on the injection site, volume, and concentration of the solution, as well as the innervation density.

Botulinum toxin treatment results in a pharmacologic recession of the injected extraocular muscle, and the muscle lengthens while its agonist contracts, paralysing it. Improved ocular alignment or a decrease in the severity of the deviation may last for a long time, even if the pharmaceutical impact normally goes away after three months.

Even after the pharmacologic effect has worn off, a number of elements, such as mechanical, proprioceptive, and binocular effects, may intervene during the period of muscle paralysis to help stabilise and improve alignment in strabismus patients over the long term.