Open-angle glaucoma, which is also called chronic simple glaucoma, is the most common form of the condition. This is the type experienced by 80 percent of glaucoma sufferers.
Open-angle glaucoma often runs in families, but does not always affect every member of the family. It can also skip one or more generations. When it does strike, it almost always affects both eyes.
The aqueous humor drains out of the eye near the "angle" formed by the cornea, the iris, and the sclera. Open-angle glaucoma gets its name because although it looks as if this angle is open-there is no visible blockage-something is preventing fluid drainage.
From somewhere inside the meshwork of channels, there seems to be some sort of increased resistance to the flow of fluid. This could be caused by: