Why Does Weed Make Eyes Red?
We commonly associate cannabis consumption with red eyes and dilated pupils. But does it have other consequences on ocular health? Even though there are still few studies dealing with the effects of cannabis on vision, we now know that this plant interferes with eye functions. No need to panic, however, since most of these symptoms resorb themselves once the plant’s effect is over! Dr Michel Pop, ophthalmologist at Cliniques Michel Pop, reviews the main effects of cannabis on vision.
Red eyes
The appearance of red eyes after having smoked cannabis is without a doubt the most visible and most well-known effect of the plant on ocular health. The THC (tetrahydrocannabinol) present in the plant lowers blood pressure, triggering a dilatation of blood vessels and an increase in blood circulation. The blood vessels of the body and the eyes then inflate and the redness appears. Although it’s striking, this effect has no consequence on the health of your eyes.
Slowing down of image processing by the retina
Another effect of cannabis on vision is to slow down the brain’s treatment of images and information. Under the influence of this plant, spatial perception is altered and eye-hand reflexes slow down. That is why it’s more cautious to consume cannabis in a secure context that is favorable to relaxation.
Eye fatigue
Cannabis can modify ocular movements and tire out the eyes, which sometimes complicates reading small characters on a screen or even the ability to understand the information one reads.
Spatial perception affected
One should never take the wheel under the influence of cannabis, especially because of the deficit in ocular movements it provokes. Indeed, spatial perception is disrupted, in particular when the eye scans the horizon to find its bearings.
Dazzlement and imbalance of near and far visions
More rarely, the pupil dilation provoked by cannabis can create dazzlements and imbalances between near vision and far vision. People who wear multifocal contact lenses can therefore suffer a diminution of their peripheral vision after having smoked a joint.
Ocular dryness and Meibomian gland dysfunction
Another effect of cannabis on ocular health is a reduction of the amount of eye blinks, which increases ocular dryness and Meibomian gland dysfunction. These symptoms can be uncomfortable for those who wear contact lenses or who have had laser surgery such as PRK, Lasik, Smile or Relex.
Cannabis consumption can normally be resumed 24 hours after an ocular operation involving the cataract, lasik, intraocular lenses and EVO+ lenses. However, it is strongly recommended to consult your surgeon on this subject first.
Lowering of ocular pressure
Because cannabis reduces ocular pressure, its consumption can seem to be a good treatment for people suffering from glaucoma, an optic nerve disease that increases ocular pressure. However, the effect of cannabis is short and diminishes a person’s capacity to function normally. That is why this option is not currently recommended for people suffering from glaucoma.
More studies must be conducted to better understand the effects of cannabis on color vision, visual acuity and the scope of the visual field. While we wait for those studies, simply be careful and cautious while consuming!
TO GO EVEN FURTHER
Keep your eyes open! Discover our best tips to preserve the health of your eyes and which foods nourish your eyes
Take care of your optic nerve: everything you need to know about glaucoma
There are many beliefs about ocular health: test your knowledge in the blink of an eye