Glaucoma causes
Glaucoma is a leading cause of irreversible blindness worldwide; it is a disease affecting the major nerve of vision in the eye, called the optic nerve. At the very least, it leads to severe vision loss, if not total blindness. Unfortunately, many people do not realize they have glaucoma until it is too late. For this reason, it is very important to have regular eye exam check-ups because early diagnosis and treatment can minimize or prevent damage to the optic nerve that occurs with glaucoma. Most often, the cause is related to the intraocular pressure of the eye; however, there are other causes to be aware of. Learn more about glaucoma and its causes in this article.
Glaucoma
As mentioned above, glaucoma is a disease affecting the optic nerve. The optic nerve plays a major role in vision; it receives light from the retina and transmits impulses to the brain that we perceive as vision. With glaucoma, a progressive degeneration of this nerve occurs, that usually begins with loss of the peripheral, or side, vision. If left undiagnosed, and therefore, untreated, it leads to central vision loss, and eventually, total blindness. Sometimes, the peripheral loss of vision isn’t noticeable and goes undetected, leading to the glaucoma being undiagnosed.
Causes of Glaucoma
Elevated eye pressure due to blockage – Elevated pressure in the eye, called intraocular pressure, is the leading cause of glaucoma. The eye is firm and round, and held this way by a constant internal pressure, in the range of 8-22 millimeters mercury (mmHg). When this pressure falls below this range, the eye becomes softer and more pliable; when this pressure is higher than this range, the eye becomes hard. As it turns out, the optic nerve (which transmits images to the brain for interpretation) is very susceptible to damage when the pressure in the eye becomes too high. The main reason for the pressure becoming elevated is due to a blocked duct.
Quick science lesson on the eye: a clear fluid, called the aqueous humor, fills the front of the eye and provides nourishment for the other structures there. This fluid is constantly produced by the ciliary body, which is the body that surrounds the lens. The aqueous humor flows through the pupil and leaves the eye through tiny channels in the trabecular network, or the eye’s own drainage system. These channels are located at the filtering angle of the eye; this angle is located where the clear cornea attaches to the iris, or colored part, of the eye. In most people, these angles are wide, but in others, they can be quite narrow. After exiting through this angle, the aqueous humor drains into capillaries and into the main bloodstream. When these channels become blocked, or at any other point if there is a blockage in this system, the aqueous fluid will not be able to exit the eye properly, and the intraocular pressure will rise, damaging the optic nerve.
Low tension glaucoma – It is possible that glaucoma can be caused by other reasons than by elevated intraocular pressure. This cause of glaucoma is not well understood, and is thought to be due to a very sensitive optic nerve, regardless of the pressure in the eye. Decreased blood flow to the optic nerve may be a contributing factor to this type of glaucoma.
Pigment abnormalities – This type of glaucoma is caused by the dispersion of pigments randomly throughout the eye. It is thought that these granules arise from the back of the iris. They can accumulate within the eye and within the trabecular network, interfering with the outflow of aqueous humor and leading to a buildup of pressure. It is possible that physical activity, like running or jogging, can stir up these pigment granules and lead to their dispersion throughout the eye and trabecular network.
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