Why Does Weed Make Your Eyes Red?

Contrary to sweepingly popular belief/opinion, the smoke produced from marijuana inhalation is not typically responsible for ocular redness in cannabis users, as the symptoms manifest themselves as well in those who consume tinctures, oils or edibles exclusively. An exception to this does exist, however, amongst those who possess allergic diseases or hypersensitivity of the immune system in relation to cannabis or THC absorption.

The root-cause, for the vast majority of cannabis users experiencing ocular redness is directly correlated with why the substance is used in treatment for people suffering from glaucoma (increased pressure within the ocular cavity). The active ingredient in cannabis (THC) lowers general blood pressure and intraocular blood pressure, as well, relieving pressure on the eye. This lowered blood pressure facilitates in allowing the blood vessels and ocular capillaries to dilate (open up) which increases the flow of blood to the eyes. Increased flow of blood equates to increased redness in the eyes. The extent/severity of the redness is categorically relative to the potency of the strain being inhaled/ingested. Strains with lower THC content, for example, may produce little or, in some cases, no redness whatsoever. Strains with higher potency, conversely, can produce significantly opposing results. The duration the effects last is variable in the same context, as well. Generally speaking, ocular redness effects will subside within 1-4 hours and have no adverse medical effects – though the evident social and societal stigma associated with redness of the eyes can be prominent.

Treating ocular redness as acquired by the absorption of THC can be relatively simple. A lack of hydration is a root contributing factor to redness, so maintaining a steady intake of water throughout the day is generally effective in, at the very least reducing the amount of redness the user experiences. Utilizing over-the-counter chemical eyedrops such as Visine, will also aid in reducing redness. These eye drops operate by re-constricting the capillaries and vessels that transport blood to the eyes – though it is worth mentioning that choosing an eye drop with both lubricants and decongestants is an ideal selection. For those interested in more natural remedies, exposing the eyelids to an ice pack for a few minutes at a time every couple of hours has been proven effective. Cooled bilberry tea (boiled fennel seeds in water) can also be repurposed as a reusable eye wash.

As to the simplest remedy? Wear sunglasses.