Natural history
Blepharospasm tends to require treatment with botulinum injections at regular intervals over long periods of time.
Medical therapy
- Botulinum toxin
- Average duration of therapeutic effect is 3 months
- Injected subcutaneously in the upper and lower lids, over the brow and at the lateral canthus, taking care to avoid a central upper lid injection which can cause ptosis.
- Normal dosage 2.5–5 units per injection site.
- Onset of effect 2–7 days post injection.
- Patients are advised to use ocular lubricants if exposure symptoms develop from incomplete eyelid closure.
- Muscle relaxants
- Muscle relaxants such as orphenadrine (Norflex) have been used effectively in mild cases of essential blepharospasm
- Methylphenidate, or Ritalin, has been described in a small case series to produce subjective improvement in 13 of 14 patients with blepharospasm (Price, OPRS, 2010).
- Ritalin is a central nervous system stimulant which blocks presynaptic dopamine reuptake by reversibly inhibiting the dopamine transporter, predominantly in the striatum.
- Ritalin also inhibits the presynaptic norepinephrine transporter to a lesser extent and norepinephrine neurons participate in regulating the release and storage of dopamine.
- Ritalin has been studied in patients with Parkinson disease and has been found to potentiate the response to L-dopa, but has no effect when administered alone.
Surgery
- Protractor Myectomy
- Originally described by Gillum and Anderson (Arch Ophthalmol 1981) to include orbicularis oculi, corrugators, and procerus. Often now performed with removal of orbicularis only.
- Reserved for patients with inadequate response to botulinum toxin
- Most still require botulinum neurotoxin even after successful myectomy, though ideally at decreased dose and frequency.
- Surgical technique is similar to blepharoplasty, removing segments of the orbicularis, pretarsal muscle is preserved so the involuntary blink remains.
- In a series of 27 patients who underwent myectomy for chemodenervation-refractory benign essential blepharospasm, Kent and co-authors identified a decreased frequency and dose requirement after myectomy. (Kent, OPRS 2015)
- Selective facial neurectomy
- Historically the first line of treatment, now rarely performed.
- Success rate had been considered 50% initially but nerve regeneration with aberrancy created an even more uncomfortable clinical picture than blepharospasm, prompting the move toward botulinum injections.
- Selective facial neurectomy targeting the zygomatic branches can reduce the adverse effects of aberrant regeneration but still can cause abnormal eyelid function and perioral muscle weakness.
Other management considerations
FL-41 tinted glasses can be helpful in reducing light stimulation.
Some patients might benefit from biofeedback or hypnosis.
Patients with apraxia of eyelid opening might benefit from ptosis surgery including levator advancement, frontalis sling (adjustable materials) or eyelid crutches.
- The objective is to facilitate eyelid opening, once the neurologic input can be generated.
Doxorubicin chemomyectomy has been reported as treatment for blepharospasm (Wirtschafter, Ophthalmology, 1998).
- Complications among 9 patients treated in the case series included skin ulcer, cicatricial ectropion, conjunctival edema, pigment mottling of skin, fat atrophy, diplopia due to Brown's syndrome.
- The minimum effective dose per treated eyelid for ranged from 1.0 to 4.2 mg.
- This treatment option should be considered only in very rare circumstances of severely resistant disease.