Macular degeneration (MD) is the highest cause of vision loss in the U.S., affecting over 10 million Americans. At present, it is considered an incurable disease. But what is happening in the eye to cause MD?
MD is a deterioration of the central part of the retina, the back layer. That layer, called the “macula,” records images and sends them back to the brain. It’s in charge of focusing vision and helps humans read, recognize faces and many more important things. Without a functioning macula, the center of the field of vision is blurry, becoming worse over time.
Macular degeneration mostly affects people over the age of 50 or 60. Right now, most treatments include injections and target endothelial cells, which line blood vessels.
VEGF, or Vascular Endothelial Growth Factor, can cause abnormal blood vessel growth around the eye. This can lead to macular degeneration.
Here’s where cannabis comes in.
Both THC and CBD have properties that some studies have shown can slow down or block the causes of macular degeneration, including VEGF. A 2004 study on brain tumours, for example, showed that THC can block VEGF pathways. This slows down the abnormal blood vessel growth in the eye brought on by VEGF.
Another study from 2008 showed that CBD can block “diabetes- and endotoxin-induced retinal damage,” which includes macular degeneration in addition to other diseases such as glaucoma.
CBD can also reduce cytokines, which are proteins that cause inflammation. Those proteins can cause retinal thickening and aid in the degeneration of the macular.
It’s important to note that research on the impact of cannabis into macular degeneration is not complete, and much of the speculation on its usefulness comes from studies into other illnesses, like brain tumors.