Although the image of red eyes after marijuana use is recognized, there is cannabis for eye health.
Compounds in cannabis take advantage of the cellular communication system called the endocannabinoid system (ECS), interacting with cell receptors found at the ocular level.
The eye and the ECS
The human eye expresses especially high levels of a receptor for cannabinoid, CB1, which is part of the nervous system of our body, both central and peripheral.
Some preclinical research has even suggested that this network plays a fundamental role as far as our vision is concerned.
A study carried out with primates in 2016 and published in Neural Plasticity made an interesting finding in which, by modifying the interaction with the ECS receptors, a change was produced in the waves measured in an electroretinogram.
The recording and measurement of these electroretinographic waves are the manifestations of the eye’s electrical response to a light stimulus, with which the researchers discovered that these receptors had an influence on the way the eye responds to light.
While the ways in which cannabis affects vision, through its interaction with the ECS, requires more research, the changes that have been seen after using marijuana are as follows:
Red-eye
That many times it can be an indicative telltale of marijuana use is due to the fact of the reduction of intraocular pressure induced by cannabis, which leads to a vasodilation of the ocular capillaries, giving rise to that recognized redness.
This side effect could be useful for those who suffer from increased intraocular pressure, as is the case with glaucoma.
Improved night vision
Some findings have suggested that some compounds such as tetrahydrocannabinol (THC) bind to ECS receptors, which could cause this night vision enhancing effect.
It has been almost for the last three decades speculation about this effect of cannabis. Since, in 1990, a pharmacologist realized that fishermen in Jamaica who ingested a cannabis preparation demonstrated an “extraordinary ability to see in the dark,” according to his words.
A study conducted in 2004 with three Moroccan subjects who used the traditional Kif, a mixture of cannabis and tobacco, showed a relationship dependent on the dose of marijuana consumed and the improvement in night vision.
Visual information processing
The evidence has shown a curious finding: the endocannabinoid system collaborates in the development of vision at the brain level.
This was demonstrated in a joint study between the University of Waterloo, the University of Auckland, and Brown University, whose tests aimed at measuring visual processing in babies who had exposure to cannabis in utero were significantly higher compared to babies whose mothers drank alcohol.
Allergic reactions
This is a reaction that some marijuana smokers experience. The allergy can be triggered by the substances present in the smoke or substances present in the plant itself.
Typical clinical manifestations include: tearing, redness of varying degrees, itching, and dry eyes. These signs and symptoms related to cannabis allergy have been reported to be very similar to hay fever in patients exposed to smoke, plant matter, and pollen, which are the main allergens in this reaction, according to the American College of Allergy, Asthma, and Immunology.
Cannabis and eye pathologies
The evidence points to the fact that cannabis could be useful in the treatment of some diseases that affect the eyes:
· Glaucoma
The severity of glaucoma is undeniable, since, in addition to pain, it causes a degeneration of the optic nerve, which ends can lead to blindness.
Researchers have been studying and researching the effects of marijuana on this disease since the 1970s. In an experience carried out with 16 people, in whom the inhalation of this herb lowered the intraocular pressure. This effect resulted in relief that lasted 3-4 hours.
Later research, carried out in the 1980s and 2000s, could show the validity of these findings.
· Neurodegenerative blindness
Research from 2014, published in Experimental Eye Research, showed evidence to suggest that cannabis compounds can prevent photoreceptor degeneration and death in inherited retinitis pigmentosa.
In this experiment, some rats received treatment based on a synthetic cannabinoid for 90 days, after which they were evaluated to see their evolution. These rats were found to have 40% more photoreceptors compared to the control group. This impressive finding could serve as the basis for cannabis-based treatments to lessen the impact of this degenerative disease.
· Diabetic retinopathy
The diabetic retinopathy is identified as one of the major complications of diabetes mellitus, leading to blindness associated, even in those patients decompensated their blood glucose levels.
A pre-clinical study carried out in 2006 found that cannabidiol (CBD) can have an ocular protective effect in diabetics, given its powerful antioxidant effect that would serve as a preventive form of vascular and retinal degeneration.
Although another study found that chronic use of this herb is associated with retinal damage, the manner of use, and the substances that are themselves causing this harmful effect would have to be evaluated.
Final Thoughts on Using CBD-Rich Alternatives
Glaucoma is one of the diseases most treated with alternatives rich in CBD from these special strains of medicinal cannabis, so they have the potential to become a useful treatment for these patients.
Unfortunately, now there is no cure for glaucoma, there are options for combining CBD with traditional medicine and thus creating a much more efficient treatment plan or even, in some cases avoiding surgical intervention. Cannabinoids are presented as a viable alternative to current treatments based on single ingredient anti-hypertensive agents. However, there is the possibility of developing tolerance to this type of molecules, within which it may be partly beneficial, if said tolerance develops only or preferentially to unwanted side effects (eg, psychotropic effects). Recently, development has been made in the use of microemulsions and cyclodextrins to overcome the barriers to ocular penetration of topically applied cannabinoids.
Perhaps the powerful antioxidant properties of cannabinoids could be beneficial in Age-Related Macular Degeneration, offering a possible alternative to established antioxidant supplements.
Studies carried out in other areas indicate that the high concentration of powerful antioxidants with neuroprotective effects contained in the cannabis plant could be of great use in other processes associated with aging, beyond visual acuity problems. To take it into consideration, as the years go by.
