Since its legalization a few months ago, marijuana has become a hot topic in many industries, including optometry.  While there is still a lot we don’t know about the long-term effects of marijuana on the eyes and vision, there are some known issues that are important to consider such as the effects of marijuana on the eye.

One of the most common and noticeable effects of marijuana on the eyes is redness. The THC in marijuana lowers the patient’s blood pressure. This causes their blood vessels to enlarge or dilate. The increased flow of blood through the blood vessels of the eye is responsible for the red appearance. Normally, this side effect of marijuana occurs soon after the drug enters the bloodstream.

There has been lots of discussion around the idea of using marijuana as a treatment for glaucoma.  Glaucoma is a common eye disease that is prevalent in the older population. An eye with glaucoma has damage to the optic nerve – the part of the eye responsible for sending information from the eye to the brain. This damage is often due to elevated intraocular pressure, which is the pressure within the eye.  Studies have shown that marijuana may lower intraocular pressure, however the level of reduction can be limited and may only last a few hours. Since marijuana can have other significant side effects on the brain and other parts of the body, it is not a recommended treatment.  There are eye drops and oral medications that can lower eye pressure more effectively with fewer side effects.

New studies are constantly arising to see if marijuana might be an appropriate alternative treatment for various conditions. In the Optometry field, in most cases it is still too early to safely determine the long-term impact on our eyes and our vision.

Dr. Justine Fung is an optometrist located at 102 Lakeshore Road East, Port Credit, and offers comprehensive eye exams for adults, children and infants.