INJECTION TREATMENT OF EYELID DISORDERS
Dr. S. Kraft
There are several disorders that cause excessive blinking or severe spasms (marked tightening) of the eyelids. Patients with these disorders find it difficult to keep their eyes open. Both the reflex and voluntary movements of the eyelids are usually involved. Two of the most severe disorders that lead to eyelid spasms are essential blepharospasm and hemifacial spasm.
1. BLEPHAROSPASM
Patients with blepharospasm show repetitive spasms of the eyelids of both eyes. Muscles around the mouth or in the neck can also go into spasm. It is thought that this disease is caused by chemical imbalances in the areas of the brain that control the movement of the muscles of the face. Treatment is directed to reducing the excessive activity of the eyelid muscles. Treatment options include oral medications, surgery to remove the overacting, or injections of botulinum toxin (BotoxTM or Xeomin TM) into the overacting muscles.
2. HEMIFACIAL SPASM
Patients with hemifacial spasm show excessive activity of muscles on one side of the face. The muscles that are most severely affected are the ones around the eye, mouth, and cheek. It is almost always caused by pressure of an artery on the nerve that controls the facial muscles where it exits from the brain. It can be cured by brain surgery to separate the nerve from the artery. The other treatment options are oral medications or injections of BotoxTM or Xeomin TM.
BotoxTM (licensed by Allergan, Inc.) and XeominTM (licensed by Merz Pharmaceuticals) are equally effective, purified preparations of botulinum toxin approved in Canada for treating these conditions. It is known to cause food poisoning and weakness in humans. However, the amount that is injected into the muscles of the face to treat these conditions is 100 times smaller than the dose that causes poisoning. No patient has had poisoning from these drugs after treatment for eyelid spasms.
The treatment involves injecting small amounts of the drug under the skin into the overacting muscles in the eyelids, eyebrows, and, if necessary, also into other areas, including the muscles around the mouth, nose, and cheek. There can be mild swelling around the injected sites, which goes away within a few hours. After the muscles are injected they become weak for an average of 3 to 4 months. After this interval the muscle strength returns to almost normal and the spasms usually come back. However, the patient’s overall condition is usually better than it was before the treatment. The success rate for treating eyelid spasms with Botox is over 90 %. However, it is not a cure: In most cases, treatments have to be repeated on an indefinite basis, at average intervals of 3 to 4 months.
Botulinum toxin can cause side effects around the eye due to spreading into structures around the eye or due to excessive weakness of the eyelid muscles . These effects are temporary in almost all cases, resolving within 4 to 8 weeks.
1. The upper eyelid can droop a few mm. (risk 1 in 50)
2. Difficulty closing the eye can lead to drying of the eye and cornea (risk 1 in 10): Artificial tears and ointments may be needed to keep the eye moist.
3. Intermittent tearing can occur as the tear film is not pumped efficiently into the tear sac. (1 in 50)
4. Rarely, the drug can reach the eye socket and cause double vision for a few days (risk 1 in 200).