Glaucoma occurs when the pressure of the fluid (aqueour humor) inside the eye (intraocular pressure or IOP) increases to the extent that it will actually push the optic nerve back into a concave shape and if it remains too high to too long it will damage the optic nerve, eventually leading to blindness.

There are many types of glaucoma however the most common is:

Primary open angle glaucoma (POAG), also known as chronic glaucoma. This accounts for 90 percent of all glaucoma cases and occurs when the trabecular meshwork becomes blocked and the fluid can not get to the normal drainage canals. this blockage results in fluid build-up and intraocular pressure. A patient’s peripheral vision decreases so gradually that they often have no awareness of it until they are only able to see objects directly in front of them.