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Can cannabis help treat glaucoma or other eye conditions?

Glaucoma is one of the reasons given for cannabis use for medical purposes.

The results of research carried out the 1970 years show that THC can reduce intraocular pressure, a key factor in glaucoma. However, the use of ophthalmic drops containing THC or related compounds has been studied, but it has not yet been possible to formulate an eye drop capable of introducing the drug into the eye at a concentration sufficient to be effective. . The first reports of this type aroused a lot of interest because at the time, conventional glaucoma medications caused a variety of undesirable side effects. But, as we will see later, other treatments for this disorder have since overshadowed hemp medicines. Conventional intraocular pressure therapies outperform cannabinoids and the next generation of glaucoma medications should treat the disease more directly or even reverse its course.

After cataract, glaucoma is one of the leading causes of blindness in the world, affecting more than 60 million people. Its most common form, the Primary open angle glaucoma (GPAO), is a slowly evolving disorder that destroys the cells of the retina of the eye and degrades the optic nerve. These losses restrict the visual field, which eventually disappears, as well as the view of the patient.

3 risk factors

The researchers have not yet learned what triggers POAG, but they identified three factors that expose individuals to a risk of developing the disease: age, race and high intraocular pressure. For example and according to the statistics: 1% of people aged 60 are suffering from POAG, while more than 9% of people over 80 are already infected.

The third risk factor, elevated intraocular pressure, results from obstruction of fluid flow that helps the eye retain its rigid form. Normally, this clear fluid, called the aqueous humor, circulates between the front of the lens and the back of the cornea. In people with high intraocular pressure, fluid flow from the anterior chamber of the eye becomes restricted, resulting in pressure build-up such as water behind a dike. Increased pressure in the eye contributes to glaucoma by reducing the flow of nutrients to the optic nerve, scientists say. Because high intraocular pressure is the only significant risk of glaucoma that can be controlled, most treatments to date have been designed to reduce it. Unfortunately, reducing intraocular pressure does not always stop or even slow down the progression of glaucoma to blindness.

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Mixed opinion of experts

Cannabis and currently available derivatives such as CBD are not necessarily an adequate treatment for glaucoma or any eye condition. To treat glaucoma, ocular pressure must be supported 24 hours on 24. Cannabis is not a practical treatment for constant use. More research is needed on the exact effects of cannabis and cannabis compounds on eye pressure and glaucoma.

Last month, a study showed that CBD seemed to increase pressure inside the eye of the mouse, suggesting that the use of this substance in the treatment of glaucoma could actually worsen the disease.

TheAmerican Academy of Ophthalmology do not recommend cannabis for the treatment of glaucoma. TheAmerican Glaucoma Society and the Canadian Ophthalmological Society agree.

In detail

Medications can alter intraocular pressure by acting on different routes of circulation of the aqueous humor. The trabecular mesh, a mesh of connective tissue and cells, is an important flow path. The liquid flows through this tissue, into a small canal and out of the eye, where it joins the bloodstream. Medications such as epinephrine or dipevefrine act by changing the shape of certain cells, which improves circulation in the trabecular meshwork. Pilocarpine, another type of drug, contracts the muscle that controls the shape of the trabecular mesh, which facilitates the passage of the fluid, while timolol, another type of drug, impedes the manufacture of fluid by the ciliary epithelium. Other medications, such as apraclonidine and brimonidine, also reduce the amount of fluid produced. Finally, another type of drug simulates the production of agents that facilitate the passage of the aqueous humor of the eye.

There are also surgical options for controlling elevated intraocular pressure. The trabecular mesh can be laser cut, which allows the fluid to come out more easily. Alternatively, a surgeon can remove a piece of the wall of the eye and allow the fluid to flow under the conjunctiva. Doctors can also insert tiny drainage tubes, similar to those used for middle ear problems, into the eye to allow fluid drainage to the outer layers of the eye. Finally, laser, heat or cold can be used to destroy the ciliary epithelium, which secretes the aqueous humor.

TABLE Glaucoma Treatments

Drug classExamplesHow does this reduce IOP
Beta-2 adrenergic agonistsepinephrine dipivineFacilitates flow through the trabecular mesh
Beta-2 Adrenergic Receptor Antagoniststimolol betaxololRemoves the production of aqueous fluid
Cholinergic agonistspilocarpineFacilitates flow through the trabecular mesh
Alpha-2 adrenergic receptor agonistsaproclonidine brimonidineReduces the production of aqueous fluid
Inhibitors of carbonic anhydraseacetazolamide dorzolamideReduces the production of aqueous fluid
Prostaglandin-F 2a similarlatanoprost unoprostoneHelps to drain excess fluid
surgeryHow does this reduce IOP
Laser modification of the trabeculumImprove the flow through the mesh
Drain tube insertionHelps to drain excess fluid
Destruction of the ciliary epitheliumReduces fluid production
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Some cannabinoids reduce intraocular pressure

Several clinical studies have shown that some cannabinoids reduce intraocular pressure (IOP) as well as most conventional glaucoma medications. This is true that cannabinoids are administered orally, intravenously or by inhalation but not when applied directly to the eyes.

In most trials, a single dose of cannabis maintained this effect for three to four hours. In addition, reduced blood pressure may reduce blood flow to the optic nerve, negating the benefits of IOP reduction.

It is possible that future research may reveal a therapeutic effect for isolated cannabinoids other than THC or produce synthetic cannabinoid analogues that last longer and have fewer side effects. But the most promising area of ​​research for treating glaucoma lies in the development of therapies that can protect or rescue the optic nerve from damage or that can restore its blood supply. There is evidence that a cannabinoid-type synthetic compound known as HU-211 has nerve-protecting properties, although it does not reduce IOP. HU-211 is chemically similar to THC, but it is not found in the marijuana plant and does not bind to the cellular receptor of brain cells as active THC.

The important thing about glaucoma is that:

The largest association of ophthalmologists and surgeons in the world does not approve cannabis or its derivatives as a treatment for glaucoma. Do not self-medicate to try to treat glaucoma. You can lose your sight if you do not have a reliable and effective treatment for glaucoma. Many current and effective treatments for glaucoma are more reliable and safer than cannabis. If you have glaucoma, you should follow your ophthalmologist's advice to get the treatment that's right for you.

SOURCE: NCBI et GLAUCOMATODAY

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