Glaucoma cause is associated with an increase in the fluid pressure inside the eye; other includes lack of adequate blood supply to the nerves.
Based on different types of glaucoma, there are many theories about the causes of glaucoma. Still, the exact cause is unknown.
What causes Glaucoma?
Primary open angle glaucoma - This is the most common form of glaucoma. Glaucoma is considering developing when the eye's drainage system becomes inefficient over time. This develops an increased amount of fluid, and a slowly build-up of pressure within the eye. Other causes of the optic nerve damage include poor circulation, or blood flow, to the optic nerves. Damage to the optic nerve is slow without symptoms, and a large portion of vision can be lost before notice the glaucoma symptoms.
Angle closure glaucoma - This type of glaucoma, also called closed angle glaucoma or narrow angle glaucoma, is a less common form of the disease. A medical emergency can cause vision loss within a day of its onset. This is an acute form of angle closure glaucoma. Although an acute attack often affects only one eye, the other eye may be at risk of an attack as well. Chronic angle closure glaucoma progresses gradually, and so it can diagnose in time and treated to avoid vision loss.
It happens when the drainage angle in the eye (formed by the cornea and the iris) blocked. Most people who develop this type of glaucoma have a very narrow drainage angle. With age, the lens in the eye becomes larger, pushing the iris forward and narrowing the space between the iris and the cornea. As this angle narrows, the aqueous fluid is blocking from exiting through the drainage system, resulting in a buildup of fluid and thus increased eye pressure.
Angle closure glaucoma can be chronic (progressing gradually) or acute (appearing suddenly).
Secondary glaucoma - This type of glaucoma occurs because of an injury or other eye disease. It may cause by a variety of medical conditions, drugs, physical injuries, and eye abnormalities. Infrequently, eye surgery can be associated with secondary glaucoma.
Normal tension glaucoma - In this form of glaucoma, eye pressure remains normal, still the optic nerve is damage. The reason behinds this is unknown. It is assuming that normal tension glaucoma may be due to an abnormally sensitive optic nerve or short supply of blood to the optic nerves caused by a condition such as atherosclerosis, a hardening of the arteries. Under these circumstances, even normal pressure on the optic nerve may be enough to cause damage.