How does marijuana affect your eyes? Can it impair your vision? Can it actually have positive effects on your eyes? Dr. Florence Fernet-Leclair answers these questions and more below.

Why does marijuana make your eyes red?

One of the most well-known side effects of marijuana is red eyes, which can occur whether you smoke, vape, eat, or otherwise consume it. Immediately after use, your sclera will still be white as your heart rate and blood pressure go up, but after about 10 minutes or so, both drop. This decrease in blood pressure leads to dilated capillaries and increased blood flow to your eyes, causing that bloodshot look. Typically, the more THC you consume, the redder your eyes become, although other factors like gender, health, and genetics play roles as well.

Can marijuana impair my vision?

Regular use of marijuana could delay the ability to process visual information by slowing the functioning of retinal ganglion cells, thereby negatively impacting eyesight. Some people will experience this more strongly than others. 

Can marijuana be helpful for glaucoma treatment?

Marijuana may offer some minor relief to glaucoma patients as it can help lower intraocular pressure slightly for a few hours; however, smoking marijuana or consuming edibles can also have negative effects on the brain and nervous system. 

There are far more effective solutions for glaucoma, including medical eye drops designed specifically for decreasing eye pressure. Book an appointment with one of our doctors today to explore your options, and find the best glaucoma treatment for your lifestyle.

What other positive benefits can cannabis have on eye health?

A recent medical study showed that cannabis may have the ability to improve night vision—at least in tadpoles. The study showed that cannabinoids help make retinal cells more sensitive to light, and improve the speed of response in dim lighting.

Whether cannabinoids have the same effect on humans and other mammals has yet to be confirmed, although some studies on Jamaican and Moroccan fishermen, as well as Moroccan mountain dwellers, show that it does.

Cannabidiol (CBD) eye drops, which can ease neuropathic ocular pain without any of the psychoactive effects of THC, are also currently being developed.