What is glaucoma?
Glaucoma is a leading cause of blindness in the U.S.
It is a disease of the eye in which the pressure within the eye is too high for the optic nerve to withstand. Fluid is constantly produced in and continuously drained from the eye. If the drain of the eye is not working properly, too much pressure can build up in the eye.
The pressure kills the nerve fibers in the optic nerve, causing damage to the peripheral vision first, and eventually affecting central vision as well.
A healthy optic nerve and an optic nerve damaged by glaucoma: note the loss of nerve fibers in the enlarged central cup.
How is glaucoma treated? Is there a cure? Glaucoma can only be controlled by attempting to decrease the pressure. Unfortunately, there is no cure. It is usually treated with eye drops first. If the drops are ineffective, a laser treatment is attempted. If all of these methods are unsuccessful, a surgical procedure that makes a new drainage channel out of the eye is attempted, in order to relieve the pressure.
Are there different kinds of glaucoma? Yes. There are four main categories of glaucoma: Open angle glaucoma, closed angle glaucoma, secondary glaucoma and congenital glaucoma. The angle is the drain that drains fluid from the eye.
Open angle glaucoma occurs when the angle, or drain, is open but is not properly draining fluid because the "clog" in the drain is further down the drainpipe. Prior to severe visual loss, open angle glaucoma has no signs or symptoms. Most people are unaware of open angle glaucoma until the very late stages. Periodic eye exams are necessary for early glaucoma detection.
Closed or narrow angle glaucoma occurs when the drain is functioning properly but is being blocked by another structure of the eye called the iris. This is usually an acute and very symptomatic form of glaucoma in which the pressure goes very high in a short time and causes redness, pain, and blurry vision. This must be treated quickly, or blindness may result within hours to days of the attack. It is usually easily treated or prevented with a laser procedure.
Another group of glaucomas, called secondary glaucomas, exists, in which the drain of the eye is damaged by a specific condition. Some of these are:
1. Pigmentary glaucoma -
the eye releases pigment, which clogs the drain
and causes the pressure to increase.
2. Angle recession glaucoma-
the drain is damaged from a blow or injury to
the eye.
3. Pseudoexfoliation glaucoma -
the eye produces a granular substance that
clogs the drain of the eye.Congenital glaucoma is another form of glaucoma. This occurs when a child is born with a malformed or blocked drain in the eye.
How is glaucoma diagnosed? Four factors are taken into consideration - glaucoma is not always diagnosed solely from pressure:
1. The health of the optic nerve: damage from
glaucoma can be seen by viewing the optic nerve
2. The visual field test, which is a test of peripheral
vision, is used to determine whether there is any loss of side vision.
3. Intraocular pressure.
4. The condition of the drain of the eye is inspected
to make sure that it is open, without damage, and
no pigment is clogging it.A patient diagnosed with open angle glaucoma is started on antiglaucoma drops and rechecked a few weeks later to ensure that the drops are working, and to check for any complications caused by the drops. Once a drop that works for you has been established, you will be examined every 3 to 6 months (depending on the severity of the glaucoma,) for the rest of your life.
I went to 2 different doctors. One said I had glaucoma and the other didn't mention anything about glaucoma. I don't know whom to believe! Eye pressure does not stay constant all day. Twice a day it rises and then declines. It should stay within normal eye pressure ranges. The two daytime peaks of pressure usually occur in the morning and later in the afternoon. Patients with glaucoma may have normal pressure until they "peak", at which point it may become abnormally high. You may have been in one office during a peak in pressure, and the other doctor's office during a low.
I heard the new drops for glaucoma don't have as many side effects as the old ones. This is true. There have been great advances in glaucoma medications in just the past 1-2 years. Until recently, Beta-blockers, (Timoptic, Betopic, Betagan, etc.) were the first choice of most physicians in glaucoma medications. Beta blockers may slow the heart, cause breathing difficulties in asthmatics, and can even cause depression. Two new drops have come on the market that appear to have fewer serious side effects. These are Alphagan and Xalatan. These new drops are very effective and only have to be used once or twice a day.
Why can't I have laser surgery for glaucoma instead of treating with drops every day? Laser surgery for glaucoma is effective for an average of five years. Drops are the most common initial glaucoma treatment. Laser surgery, either as initial therapy or as an adjunct to the drops, is an alternative to drops.
|
