Botulinum toxin A-induced protective ptosis in corneal disease.

Botulinum toxin A produces a temporary, flaccid ptosis when injected into the levator palpebrae superioris muscle. The resulting protective ptosis was used to aid healing in 21 cases of indolent ulceration, and, prophylactically, in 4 cases of neuroparalytic keratitis. Of the indolent ulcers, 90% healed completely. In all but one case, the cornea was covered completely by the lid and complete ptosis was produced in 75% of cases in an average of 3.6 days, lasting for 16 days on average before recovery began. Recovery of levator function was complete in 8.5 weeks on average. Superior rectus underaction was seen in 68% of cases but this recovered completely in all cases in an average of 6 weeks. Impression cytology showed a trend toward normal conjunctival morphology as healing progressed.