Patients who have various diseases of the cornea (the “watchglass” at the front of the eye) may develop loss of the covering (or surface) layer, known as the epithelium. This leads to pain and irritation, as well as reduced vision. When treatment of the cornea condition does not result in successful healing of the defect in the surface layer, it may be necessary to shut the eye to allow proper healing.
In the past this required minor surgery in which the eyelids are temporarily closed using stitches (tarsorraphy). The eyelids are reopened once the cornea is healed.
An alternative to surgery on the eyelids is the use of BotoxTM to create a temporary closure of the eye. Small amounts of Botox are injected into the upper eyelid and under the brow above the eyeball. This leads to a painless droop (“ptosis”) of the upper eyelid which nicely covers the cornea throughout the day and night. This approach has the advantage of allowing the surgeon to easily check the status of the cornea by simply lifting the drooping eyelid. This contrasts with the situation after the surgery option, where the view of the cornea can be less than optimal since the eyelids are stuck together by the surgery.
BotoxTM is a purified preparation of botulinum toxin (distributed and licenced by Allergan, Inc.) Excessive amounts of this substance is known to cause food poisoning and weakness in humans. However, the amount that is injected into the eyelids to induce a droop of the eyelid is 300 times smaller than the dose that causes poisoning. No patient has had poisoning from this drug after being treated with injections into the eyelid.
There are rare instances of side effects: