Glaucoma is a group of eye diseases that affect the optic nerve, generally causing damage to the optic nerve.
The optic nerve is the connection between the eye and the brain, and is actually the 2nd cranial nerve, coming out from the brainstem. As you may imagine, it is an extremely important part of the visual system.
A basic framework for a layperson to think of the optic nerve is as the "HDMI cable" connecting the eye to the brain. If the "cable" is damaged, then the signal may not "fully transmit".
Once we have the framework of what glaucoma is - damage to the optic nerve, we can then start discussing "why" it happens, and what we see anatomically.
Most commonly, the optic nerve gets damaged related to elevated eye pressure, within the eye itself. This can cause increased "cupping", or "thinning", of the optic nerve.
Every healthy eye has an intrinsic pressure, which is why the eye looks like a grape and not a raisin. However, when that pressure is too high, it can damage the optic nerve, causing glaucoma.
There are a few reasons why the eye pressure can be elevated, and that is generally described by the basic different types of glaucoma: Open angle glaucoma and narrow angle glaucoma.
This is, however, for a different blog post!
Until next time,
-Jeff