Glaucoma is a multifactorial disease process of the optic nerve inside of the back portion of the eye. The optic nerve contains nearly 1.5 million nerve fibers and is the size of a thin pencil. The optic nerve transmits the visual information from the retina to the vision center in the back portion of the brain called the occipital lobe. In the simplest terms, glaucoma is the result of the eye pressure inside the eye being higher than the optic nerve can tolerate. This leads to a slow death or damage to the optic nerve fibers. Slowly over time the nerve continually loses nerve fibers leading to blindness.
There are approximately 3 million people in the United States with glaucoma. Nearly half of those people do not know they have glaucoma. Glaucoma is the second leading cause of permanent blindness in people over age 65 only behind macular degeneration in the United States. Worldwide, glaucoma is the second leading cause of blindness behind cataracts.
The ciliary body located behind the iris (colored portion of the eye) slowly produces fluid called the aqueous humor. The aqueous humor supplies nutritional material to the structures inside the eye and keeps the eye formed to its proper structure. The fluid passes through the pupil into the anterior chamber of the eye. The anterior chamber is the fluid filled space between the iris and the cornea (clear portion of the eye in front of the iris).
Inside the anterior chamber at the junction of the iris and the cornea inside the eye is a structure called the trabecular meshwork. On the outside of the eye, it is located underneath the junction of the cornea and sclera (white portion of the eye). The trabecular meshwork looks like cheese cloth and the fluid percolates through the meshwork into a drainage channel called Schlemm’s canal. The aqueous humor passes from Schlemm’s canal into venous canals on the surface of the eye into the blood system. There is a constant production of fluid inside the eye and a constant flow of fluid from the eye. A normal eye pressure is maintained by this system.
In the most common type of glaucoma, the meshwork gradually becomes obstructed with debris which limits the flow of fluid out of the anterior chamber. This obstruction raises the pressure inside the eye. The increased eye pressure causes damage to the optic nerve resulting in blindness over time.
It is believed that the eye pressure inside the eye limits or diminishes the blood flow in the optic nerve and this causes the damage to the nerve. Just like when you blow up a balloon and the balloon becomes tighter with more air, it becomes harder to force more air into the balloon. The eye pressure inside the eye reduces the flow of blood into the eye because of the increased resistance.
As stated at the start, there are many factors that contribute to the development of glaucoma and damage to the eye from glaucoma. Eye pressure is the major factor but there are many others.
But, the good news is, you do not have to lose your vision from glaucoma. You need to follow your eye doctor’s recommendations, stay compliant with your medications, keep your eye appointments, and if there is any question about your treatment seek a second opinion.
You can trust James E. Croley III, M.D. to treat your glaucoma. At the age of 14, Dr. Croley made the commitments to become an Eye M.D. and help people with vision problems. Dr. Croley moved to Southwest Florida in 1980 to open his practice and since he has been very active in the development of new advances in Ophthalmology. He has traveled extensively across the nations and overseas, consulting with other Eye M.D. to promote excellence in eye care.
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