Cannabis and Glaucoma

Glaucoma is a group of eye diseases that cause progressive damage of the optic nerve at the point where it leaves the eye to carry visual information to the brain. If left untreated, most types of glaucoma progress (without warning nor obvious symptoms to the patient) towards gradually worsening visual damage and may lead to blindness. Once incurred, visual damage is mostly irreversible, and this has led to glaucoma being described as the “silent blinding disease” or the “sneak thief of sight”.

Glaucoma is the second most common cause of blindness worldwide. It is estimated that 4.5 million persons globally are blind due to glaucoma and that this number will rise to 11.2 million by 2020. It is noteworthy that due to the silent progression of the disease – at least in its early stages – up to 50% of affected persons in the developed countries are not even aware of having glaucoma. This number may rise to 90% in underdeveloped parts of the world.

The most common types of adult-onset glaucoma are Primary Open Angle Glaucoma (POAG) – a form most frequently encountered in patients of Caucasian and African ancestry – and Angle-Closure Glaucoma (ACG), which is the more common in patients of Asian ancestry. Angle-Closure Glaucoma is often chronic, like POAG, but can sometimes be acute, in which case it usually presents as a very painful ocular condition leading to rapid vision loss.

There is no cure for glaucoma as yet, and vision loss is irreversible. However medication or surgery (traditional or laser) can halt or slow-down any further vision loss. Therefore early detection is essential to limiting visual impairment and preventing the progression towards severe visual handicap or blindness. Only a limited number of medications can be used to treat this condition.

Currently, glaucoma is one of those conditions for which Americans could get a medical cannabis recommendation in 25 states in the USA, as some early science from the 1970s demonstrated cannabis had the ability to reduce the pressure inside the eye.

Here's a brief recap of what research found so far regarding the potential for medical cannabis to treat glaucoma.