[Botulinum toxin treatment for crocodile tears, spastic entropion and for dysthyroid upper eyelid retraction]

After proximal facial nerve lesions, misrouting of nerve fibres may cause the phenomenon of crocodile tears. Transconjunctival injections of botulinum toxin in the palpebral part of the lacrimal gland are the treatment of choice. An initial dose of 2.5 U of toxin is recommended, and injections may be repeated after 6 months if symptoms reoccur. Botulinum toxin A is also a highly effective temporary treatment for involutional (spasmodic) entropion until surgery is performed. A dose of 10 U of botulinum toxin is injected in the pretarsal part of the lower lid near the eyelashes. Botulinum toxin treatment is also effective for dysthyroid upper eye lid retraction, especially in instable thyroid disease or mild retraction. Slight transient ptosis may occur in some cases. Depending on the amount of retraction, a dose of 5 or 7.5 U of toxin is injected into the subconjunctival space at the superior margin of the tarsal plate.