Glaucoma is the second leading cause of blindness in North America, behind
diabetes. In glaucoma, the optic nerve (the nerve carrying information from
the eye to the brain) is damaged by a build-up of fluid in the eyeball.
The front of the eye is filled with a clear liquid that supplies the eye with
oxygen and nutrients and keeps it inflated. A gland behind the upper eyelid
produces a steady supply of this liquid, and it normally drains out through
a mesh of tiny holes behind the lower eyelid. In glaucoma, the liquid is produced
normally, but it cannot drain out of the eye. This causes pressure to build
up in the eye, pressing on the optic nerve. The nerve cells slowly lose their
blood supply, eventually dying. The outer nerves fail first, so vision loss
tends to start at the edges, progressing to "tunnel vision" and blindness.
Many people don't notice this at first, and there's usually no pain, so glaucoma
is often quite advanced before it's detected.
The good news is that with early treatment, vision loss can be minimized or
prevented. Because glaucoma isn't obvious, it's vital to get your eyes checked
regularly, especially if you have any of these risk factors:
- family history of glaucoma
- are of African descent
- nearsightedness
- previous eye injury
- high blood pressure
- diabetes
- long-term use of prednisone, cortisone, or other steroids
Adults should have their eyes checked every one to two years up to the age
of 65, and every year after that. But if you have any of these risk factors,
you should go as often as your eye care professional recommends. At the check-up,
the optometrist will measure the pressure in your eye, look at the optic nerve
for signs of damage, and check your peripheral vision. If glaucoma is suspected,
you will probably be referred to an ophthalmologist (a physician specializing
in eye disorders) for treatment. Glaucoma is usually treated with eye drops
that lower the pressure in the eye. In some cases, surgery may be needed.
