Glaucoma is a disease involving damage to the optic nerve. The most common cause of glaucoma is higher-than-normal eye pressure.
The optic nerve is made up of a million tiny nerve fibers that carry information from the eye to the brain where images are formed of what our eyes see. The system functions like a video camera (the eye), connected by a cable (the optic nerve) to television (the brain). When exposed to high intraocular pressures for prolonged periods of time, the optic nerve fibers begin to die and consequently cannot relay visual information from the eye to the brain. This can also occur at normal pressures if you inherited a particularly weak optic nerve or have episodes of very low blood pressure.
What causes increased pressure in the eye?
The normal eye maintains its spherical shape (like an inflated balloon) by means of a watery fluid, called the aqueous humor, which is constantly secreted within the eye. As this fluid slowly drains out of the eye and into the bloodstream through small channels in the wall of the eye, the eye pressure is maintained at a constant, normal level. In contrast, tears are produced by glands around the eye and are totally different than the aqueous humor inside the eye.
If the aqueous drainage channels are blocked so that aqueous fluid is trapped inside the eye, then the pressure may build up to dangerous levels. Because the eye is a closed structure, this elevated eye pressure will push and damage the weakest part of the eye where the optic nerve fibers leave the eye at the optic disc. Loss of these nerve fibers causes “cupping” of the optic nerve. Cupping is one of the earliest signs of glaucoma.
If untreated, vision loss or blindness will occur. Loss of optic nerve fibers causes blind spots to develop, usually in the peripheral (side) vision. This early loss often begins near your nose (which we tend to ignore) so it is rarely noticed by the patient. With continued high pressures, irreversible damage to the optic nerve causes loss of reading (central) vision & eventual blindness.
Fortunately, blindness is uncommon with early detection and regular treatment, like the care and expertise provided at EyeHealth Northwest. Patients participating in routine prevention and quality treatment regimens, significantly decrease their risk of vision loss & blindness.
Unfortunately, those who do not know that they have glaucoma and those who have been diagnosed but fail to keep regular follow-up visits are at the greatest risk of blindness. The vision loss caused by glaucoma is permanent since the optic nerve cannot be replaced or repaired, not even at the best eye centers around the world. Because of this, Glaucoma is the second leading cause of blindness in the US and the first cause of preventable blindness.