Medical Marijuana and Glaucoma
Does marijuana help glaucoma? Only briefly: THC lowers eye pressure for a few hours, and NIH says cannabis isn’t helpful for glaucoma.
Glaucoma is on Florida’s list of qualifying conditions in section 381.986(2), which is one reason people ask about using marijuana medicine for it. NIH’s complementary health center has reviewed that research, and its findings are summarized below.
As an eye condition, glaucoma damages the optic nerve, and many people with it have high pressure in the eye, though NEI says scientists aren’t sure what causes the most common types. Without treatment, glaucoma can eventually cause blindness, according to NEI. Traditional treatment is mostly based on early detection and prevention, while there are also other therapeutic strategies. Studies of marijuana and glaucoma date back to the 1970s and 1980s; they found it lowered eye pressure, but not as well as existing treatments.
But, does marijuana help glaucoma? What are the benefits of marijuana for glaucoma? And is marijuana good for glaucoma at all? The studies behind that answer, and what each one found, follow.
What Causes Glaucoma?
As mentioned, glaucoma is an eye disease that causes vision loss due to optic nerve damage. While it is true that the most common cause is ocular hypertension (abnormally high pressure within the very eye), glaucoma has several types, various contributing factors, and can manifest in different ways. Doctors are also suspecting that a patient’s dietary habits, ethnicity, genetics, and some other causes are linked to the condition.
Types of Glaucoma:
- Open-angle glaucoma
- Angle-Closure Glaucoma
- Normal-Tension
- Congenital
- Secondary
- Pigmentary
- Uveitic
- Iridocorneal Endothelial Syndrome (ICE)
- Neovascular
- Traumatic
- Pseudoexfoliative
The open-angle type is the most common form of glaucoma in the United States. It is also called primary, simple chronic glaucoma, or wide-angle glaucoma, and it describes the open angle where the cornea meets the iris. It is caused by clogged canals, which directly elevate eye pressure.
Can Marijuana be Used for Glaucoma Treatment?
It is a common opinion that most glaucoma types are life-long conditions, and, when developed, treatment is mostly focused on preventing the deterioration and further decrease of the vision. There are various surgeries, both conventional and laser, focused on preventing further nerve and glaucomatous damage, but there is no guaranteed glaucoma treatment.
Marijuana treatments are, as mentioned, studied for the past half-century.
Medical marijuana and glaucoma treatment tests are based on the ability of cannabis to lower intraocular pressure. This is usually attempted with oral administration, smoking, and even intravenously, while the typical application to the eye, as with other glaucoma treatments, is not a valid method here.
How Well Does Medical Marijuana Work for Glaucoma?
Is marijuana good for glaucoma at all? In short, no. NIH’s complementary health center notes that cannabis lowered eye pressure in studies, but not as effectively as treatments already in use.
A key limit is time: in a 2006 pilot trial of 6 patients, one 5 mg dose of THC lowered eye pressure at 2 hours, but pressure was back to baseline after 4 hours, so control around the clock would need frequent doses.
NIH concludes that cannabis isn’t helpful for glaucoma, and in the 2006 trial a 40 mg dose of CBD actually raised eye pressure.
Ways to Use Medical Marijuana for Glaucoma?
If NIH finds cannabis isn’t helpful for glaucoma, why does it still come up? Partly because of state law. Glaucoma is one of Florida’s qualifying conditions, so a qualified physician may certify a patient with it after an in-person exam, but eye drops, laser treatment and surgery remain the proven treatments.
Does Marijuana Help Glaucoma Even a Little Bit?
The bottom line is that the causes of the most common types are not fully known, but lowering eye pressure is proven to slow the disease. Eye doctors can diagnose and treat glaucoma even when its exact cause is unknown.
Standard glaucoma drugs have side effects too, which is one reason some patients ask about alternatives. For instance, carbonic anhydrase inhibitor pills such as acetazolamide can cause side effects like upset stomach, loss of appetite, tingling and drowsiness. Miotic agents, like pilocarpine, cause a range of adverse effects from diarrhea to vasodilation, and more.
That is one reason research into glaucoma treatments with fewer side effects continues. When eye drops are not enough, laser treatment and surgery are options; NEI says treatment cannot undo vision loss but can stop it from getting worse.
Do not stop your glaucoma treatment to use marijuana. If you have glaucoma, talk with your ophthalmologist, and if you live in Florida, schedule a consultation with our Sarasota or other Florida offices to ask about certification.
