Types of Glaucoma
Aqueous humor normally exits your eye through a drainage system at the angle where the iris and the cornea meet. When the drainage system doesn’t work properly, the aqueous humor can’t filter out of the eye at its normal rate, and pressure builds within your eye.
Primary Open-Angle Glaucoma
In primary open-angle glaucoma, the drainage angle formed by the cornea and the iris remains open, but the microscopic drainage channels in the angle (called the trabecular meshwork) are partially blocked, causing the aqueous humor to drain out of the eye too slowly. This leads to fluid backup and a gradual increase of pressure within your eye. Damage to the optic nerve is painless and so slow that a large portion of your vision can be lost before you’re even aware of a problem. The exact cause of primary open-angle glaucoma remains unknown.