[Botulinum toxin injections for the treatment of strabismus. Which indications are still useful today?].

Botulinum toxin treatment was originally developed 25 years ago by Alan B. Scott to produce reversible weakening of extraocular eye muscles in humans (chemodenervation). The following uses are still helpful today in comparison with eye muscle surgery, prism applications etc.: Preoperative evaluation of possible postoperative diplopia in patients in whom this cannot be done by means of prisms or traction test, etc. Acute paretic loss of ocular muscle function when surgical treatment of the ocular muscles is not yet possible but the patient is obviously disturbed by diplopia or a forced head posture. This applies especially to VI cranial nerve paresis. Depending on the surgical approach in VI nerve palsies, Botulinum toxin may be injected in the medial rectus muscle before muscle transposition surgery to loosen contracture. Strabismus in acute Graves' disease. In strabismus in other conditions, Botulinum toxin is mostly inferior surgical treatment of the ocular muscles; this is the case, for example in congenital esotropia or horizontal strabismus in adults. While the reversibility of the Botulinum toxin A effect by fading out after 3-4 months is seen as an advantage, it does also mean that in these cases of constant strabismus it is necessary to keep repeating the injections.