In eyelid spasms, muscle spasms occur when the eyelid closes, which practically means blindness. Therapies such as medicinal elimination of the cramped muscles with Botox or surgery do not always bring success.
A small Israeli double-blind study of six sufferers shows that a sublingual cannabis extract has an alleviating effect: Seizure duration decreased significantly, as did frequency and severity of seizures. One-hour eyelid spasms lasted only a few minutes under cannabis therapy.
In addition to THC, the cannabis extract contained CBD and other plant constituents such as terpenes. Medical cannabis may be an effective treatment option for sufferers for whom Botox does not work, the research team said.
Eyelid spasm – What is it?
Eyelid spasm (Benign essential blepharospasm) is a movement disorder (dystonia) of the orbital and facial muscles. The neurological disorder involves involuntary muscle spasms during eyelid closure. Affected individuals are virtually blind during the spasms and thus suffer very severe impairment.
The disease begins at the age of 50 to 70 with eye complaints (such as frequent blinking, dry eyes), and later permanent eyelid spasms develop. In the USA, 20,000 to 50,000 people suffer from the disease. Common therapy uses Botox (botulinum toxin injections) to paralyze the cramped muscles or surgery.
Anticholinergic and antiepileptic medications are palliative but have side effects, especially in the elderly. Eye dryness and ptosis (eyelid muscle weakness with drooping of the upper eyelid) are other complaints.
Prospective double-blind study with 6 affected persons
The research team selected six participants (out of an original 21 people) for the double-blind study between March 2019 and February 2020. Botulinum toxin was ineffective in the subjects, who were on average 65 years old. The 3-month study consisted of two sections, each lasting 6 weeks. Three subjects were randomly assigned to each of the therapy and placebo groups.
The therapy group took a cannabis oil of the “Erez” variety sublingually (under the tongue) at night for 3 months. The oil contained mainly THC (3.2%). Other cannabinoids included CBD (0.1%) and 3.3% other cannabinoids. Other plant constituents included terpenes, flavonoids, waxes, and chlorophyll (leaf green).
Participants in the placebo group received a placebo for 6 weeks, following cannabis oil as well in the subsequent study phase. The patients adjusted their individual drop dosage under medical supervision.
They also kept a patient diary and noted:
- Number and duration of spastic attacks
- Severity of the attack (scale from 1 to 4)
Cannabinoids shorten convulsions to a few minutes
Already in the first study phase (1st to 6th week) cannabis was able to significantly reduce the duration of cramps: In the therapy group, an eyelid spasm lasted an average of 4.29 minutes, whereas in the placebo group it lasted 73.9 minutes – the cannabis-drops therefore reduced eyelid spasms lasting over an hour to just a few minutes.
The placebo group also took cannabis-drops in the second study phase (week 7 to 12) – with pleasing results: seizure duration decreased significantly from 73.9 minutes under placebo to 8.96 minutes. Participants were able to reduce seizure duration to less than 10 minutes with 6 weeks of cannabis therapy. The therapy group achieved further improvements in the second half of the study: Compared to the first study phase, attacks decreased to 1.77 minutes, more than halved.
The number of seizures also decreased in the second half of the study: While 94 attacks were counted in the placebo group, only 61 were counted under cannabis. Cannabis therefore reduced the number of eyelid seizures by one third. However, the result is not statistically significant – the study of six subjects is too small.
The cannabis drug was well tolerated. Side effects on the eye were absent. Mild reactions were fatigue, dry mouth and insomnia.
The study results in an overview (number of drops taken, number and duration of convulsions):
|Study Phase||Placebo Group||Cannabis Group|
|Week 1 to 6||6,81 drops|
|Week 7 to 12|
(both groups received Cannabis)
|Week 1 to 12||73 spastics|
severity of spastics 2,54
severity of spastics 1,56
Endocannabinoid system in blepharospasm
The causes of blepharospasm have not been conclusively investigated. Brain imaging studies suggest dysfunction of the basal ganglia, thalamus, and cerebellum. The endocannabinoid system controls movements, among other things. The basal ganglia contain abundant cannabinoid receptors. Phytocannabinoids from the cannabis plant, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), influence these receptors and can thereby alleviate movement disorders.
- Tetrahydrocannabinol (THC) has a psychotropic effect, i.e. mind-altering. THC may have therapeutic potential for glaucoma, muscle spasticity, loss of appetite and sleep disorders.
- Cannabidiol (CBD) relieves neurological symptoms without intoxicating. Possible applications are epilepsy, inflammation, migraine and psychiatric disorders.
A case report published in 2004 showed for the first time that dronabinol (synthetic THC) relieved symptoms of blepharospasm.
After unsuccessful treatment, the patient reported improved social life and pain relief after several weeks of dronabinol therapy.
Both THC- and CBD-dominant cannabis medications can assist with blepharospasm, although previous studies on dystonic disorders mostly examined THC.
Larger studies needed
The researchers conclude that medical cannabis is an effective and safe second-line treatment for eyelid spasm when Botox is not sufficient. Cramp duration decreased sharply, as did frequency and severity of cramps.
However, 6 weeks of cannabis treatment may be too short, as the therapy group had better results from 3 months of cannabis therapy than the placebo group after 6 weeks of cannabis use. Therefore, the researchers concluded that a 3-month therapy with THC-dominant cannabis oil can alleviate blepharospasm symptoms with good tolerability.
Since the study was small with 6 participants, future larger studies are needed. In addition, studies on other dystonias of the eye should be conducted.
Zloto O, Weisman A, Avisar I, et al. Medical cannabis oil for benign essential blepharospasm: a prospective, randomized controlled pilot study. Graefes Arch Clin Exp Ophthalmol. 2022;260(5):1707-1712. doi:10.1007/s00417-021-05533-1