Botulinum toxin therapy of strabismus

Botulinum toxin therapy of strabismus is a medical technique used sometimes in the management of strabismus, in which botulinum toxin is injected into selected extraocular muscles in order to reduce the misalignment of the eyes. The injection of the toxin to treat strabismus, reported upon in 1981, is considered to be the first ever use of botulinum toxin for therapeutic purposes. Today, the injection of botulinum toxin into the muscles that surround the eyes is one of the available options in the management of strabismus. Other options for strabismus management are vision therapy and occlusion therapy, corrective glasses (or contact lenses) and prism glasses, and strabismus surgery.

The effects that are due only to the toxin itself (including the side effects) generally wear off within 3 to 4 months. In contrast, improvements in alignment may be long-lasting, particularly in two circumstances. First, if the "antagonist" muscle (the muscle pulling in the opposite direction) is active, the injected muscle will be stretched, and may permanently lengthen by adding tissue during the period of toxin paresis.^{[citation needed]} Second, if binocular vision has been achieved and stabilized, alignment may "lock in". There are indications that botulinum toxin therapy is as successful as strabismus surgery for patients with binocular vision and that it is less successful than surgery for those who have no binocular vision.^[1]