Nitric oxide has become a popular dietary supplement—usually in the form of beetroot juice—because it can help improve blood flow and lower blood pressure. As it turns out, nitric oxide also works as a glaucoma treatment. And no, it’s not just eating beets and green leafy vegetables. This novel eye drop could be the first glaucoma treatment to lower intraocular pressure by using nitric oxide to target the trabecular meshwork.
How Nitric Oxide Works in the Body
Nitric oxide is a gas that’s naturally produced inside the body. It only survives for a few seconds, but that’s all the time it needs to make quite an impact on your health. One of its jobs is to relax blood vessels, which improves blood flow and lowers blood pressure. Nitric oxide regulates blood flow in the brain, prevents atherosclerosis, and helps heal wounds, repair muscles and fight bacteria.
Nitric Oxide Regulates Intraocular Pressure
Inside the eye, fluid called the aqueous or vitreous humor (depending on whether it’s in front of or behind the lens) provides the pressure needed to hold the eye’s shape. The amount of aqueous fluid and its flow in the front of the eye determine whether intraocular pressures goes up or down, so several mechanisms regulate the fluid’s volume by making sure that the amount of fluid released in the front of the eye is offset by allowing drainage. One of these mechanisms is the trabecular meshwork.
The trabecular meshwork is like a one-way valve that opens to let aqueous humor circulate and drain in the front of the eye. When the meshwork fails—which can be due to normal aging of cells, DNA damage or other causes—fluid can’t circulate properly, intraocular pressure builds and glaucoma develops.
So how does all of this relate to nitric oxide? It turns out that the trabecular meshwork is regulated by cells that depend in part on nitric oxide. Glaucoma treatments work by lowering intraocular pressure, but none of the current medications affect the trabecular meshwork directly. That may be about to change. After many years of trial-and-error, researchers have finally developed a medication that uses nitric oxide to target the trabecular meshwork.