 |
 |
 |
 |
 |
Common Eye Diseases :: Glaucoma |
 |
 |
 |
 |
 |
|
|
|
GLAUCOMA-Suresh G. Kamath, M.D.
More than two million Americans suffer from Glaucoma and about 100,000 of them are blind. Glaucoma is one of the most dangerous diseases one can have because the most common type (Open Angle Glaucoma) is a silent but progressively blinding disease. Few people know they have this disease because there are usually no symptoms until one is almost blind.
Glaucoma is a disease of the Optic Nerve. If one imagines the eye like a video camera and the brain like a monitor the Optic Nerve is the cable that connects the two. When one sees a face, for example, the eye takes a picture and sends the picture as an electric signal over the Optic Nerve to the brain. The brain processes the picture and then we recognize the face as that of a loved one. In order to see, all three parts of the visual system (the eye, the Optic Nerve, and the brain) must work properly. If the circuit is broken at any step-the picture quality is poor or lost. In Glaucoma the Optic Nerve becomes sick. This is like the cable between the camera and monitor getting frayed or damaged. Therefore the picture signal to the brain is degraded and eventually lost.
It is not understood why the Optic Nerve gets sick. Theories include problems with blood flow or circulation, eye pressure changes and genetics. Open Angle Glaucoma (OAG) can occur at any age but is most commonly seen in the elderly. Individuals with a family member with OAG may have up to ten times the normal risk of getting the disease. It is also much more common among African Americans. Patients who have Diabetes, are on certain medications (like Prednisone), or who have had previous eye surgery or injuries are much more prone to the disease. Unfortunately the gene or genes for Glaucoma have not been absolutely defined-but research is ongoing. At this point we only know that the patients in the previous risk groups should be examined periodically to try to catch the disease as early as possible.
Early detection and ongoing treatment of Glaucoma can reduce the risk of blindness. All adults should be examined by an Ophthalmologist every two years-and persons in those high risk groups should be examined at least once a year.
An Ophthalmologist is a surgeon (M.D.) specializing in eye disease. Typically the examining Ophthalmologist will take a complete medical and family history to determine the patient's risk factors. Then a complete examination of the eye-especially the Optic Nerve, the eye pressure and certain other eye structures that can aid in the diagnosis is completed. Patients with abnormalities in the examination will then have a Visual Field Test.
A Visual Field Test is done with a special computer and a projection screen. The computer flashes lights on different areas of the screen. The patient presses a button when she notices each of these flashes. At the end of the test the computer paints a picture of the areas that the patient saw well and also the areas that the patient didn't see well or could not see at all. Certain patterns of blind spots on this Visual Field Test can help diagnose Glaucoma.
Patients with abnormal Optic Nerves and characteristic blind spots on the Visual Field Test have Glaucoma and should be treated.
Patients with abnormal Optic Nerves but a normal Visual Field are classified as .Glaucoma Suspects.. Diabetics and patients with a family history of Glaucoma are usually Glaucoma Suspects as well. Glaucoma Suspects are monitored closely. How often a Glaucoma Suspect is reexamined depends on how abnormal the Optic Nerves and other parts of the examination appear.
Eye pressure is another factor that is often evaluated in Glaucoma Suspects and Glaucoma patients. The pressure in the eye has no direct relationship to the patient's blood pressure. The .normal. eye pressure is between 10 and 22 (millimeters of Mercury). Eye pressure fluctuates over the course of the day. The pressure can fluctuate as little as one or two points at different times of day for one patient and more than ten points at different times of day for another. The peak or high pressure for the day can occur at different times of day for different patients.
Eye pressure should be measured directly with a device that touches the surface of the eye (the Cornea). There are several such devices that are very accurate. The air puff technique can be extremely inaccurate-and should not be relied on for the management of Glaucoma.
Unfortunately the eye pressure alone does not determine whether one has Glaucoma. A patient with Glaucoma can have eye pressures that are above, below or within the .normal. range. By definition, a patient has Glaucoma when the Optic Nerves and Visual Field Tests are abnormal, regardless of the eye pressure. However, if a patient's eye pressure is much higher than .normal,. this also qualifies the patient as a Glaucoma Suspect (these patients are called Ocular Hypertensives = high eye pressure). Some Ocular Hypertensives are treated as if they have true Glaucoma because they are at high risk of suffering Optic Nerve damage from the elevated pressure.
Treatment for Glaucoma may include medication (usually as eye drops or occasionally pills by mouth), laser therapy or eye surgery. Which treatment or combination of treatments depends on the severity of the Glaucoma and the patient's particular situation. Treatment is tailored specifically to the individual patient. There is no .cookbook. formula for treatment (There is no .one size fits all.).
We live in a golden age of Glaucoma medications. We have a wide variety of drugs from which to choose. Patients who are allergic to or fail to respond to one drug can try others or combinations of others. The goal of therapy is to reduce the eye pressure-regardless of whether it is high, low or .normal. at the start. Occasionally, medical treatment fails or is not enough. These patients may require laser treatments that help lower the eye pressure or keep the pressure maintenance system of the eye open. In some cases surgery that makes a new controlled opening in the eye as a kind of a pressure releaser or .pressure relief valve. may be necessary.
Regardless of the treatment required, most patients can achieve control of Glaucoma with aggressive and ongoing treatment. Glaucoma cannot be .cured.. The damage done by Glaucoma cannot be reversed. However, Glaucoma can be controlled. Further damage or visual loss from Glaucoma can be slowed down or stopped!
The key to Glaucoma is early diagnosis. Treating the disease early and aggressively can reduce the risk of going blind.
STEROID INDUCED GLAUCOMA
Steroids (Prednisone and its cousins) can cause elevation in eye pressure (Ocular Hypertension) in some susceptible people (steroid responders). If Optic Nerve damage occurs and/or if ongoing steroid treatment is needed (as in emphysema, asthma, arthritis, Lupus, etc) Open Angle Glaucoma (OAG) may develop. In most patients, stopping the steroids will lead to a return to normal pressure. In some patients treatment for OAG as described above is necessary.
ANGLE CLOSURE GLAUCOMA
We have discussed the most common type of Glaucoma above (Open Angle Glaucoma or OAG). A less common type of Glaucoma is .Angle Closure Glaucoma. (ACG). Angle Closure Glaucoma is a completely different disease. In ACG, the system that controls the pressure in the eye suddenly closes off causing a sudden increase in eye presssure. This sudden enormous increase in eye pressure can lead to eye pain, redness, light sensitivity, blurry vision, haloes, headache, nausea, vomiting, and near fainting. Some patients may only have mild symptoms.
ACG can occur at any age but is more likely to occur in or after middle age and in some people who have a certain type of extremely thick glasses (but usually not the near sighted type. This type of thick eyeglass prescription is not the cause of the Glaucoma. It is a sign of the abnormal anatomy of the eye that leads to this type of Glaucoma).
Immediate treatment for ACG is necessary to prevent permanent blindness and ongoing pain. Treatment usually involves lowering the eye pressure with eye drops and medications by mouth and/or intravenously followed by reopening the pressure valve system with laser or surgery.
Suresh G. Kamath, M.D.
|
|
|
 |
 |
 |
|
|
|
|
|
|
See also... |
|
|
|
|
|
 Overview
Cataract - Article 1
Cataract - Article 2
Glaucoma
Dry Eye
Blepharitis
Macular Degeneration
| |
|
Suresh G. Kamath, M.D. is a Board Certified Physician and Surgeon. Dr. Kamath specializes in the medical and surgical care of the eye (Ophthalmology), eyelids and skin (Eye or Oculoplastic Surgery).
Our mission at Capital Eye Care is to provide excellent care in an environment that combines education, clinical leadership and service to the community.
We offer office based surgery for most eyelid and skin procedures for adults.
We accept all new and established patients for routine, emergency and elective/cosmetic visits.
We accept patients age seven and above.
| |
|
|
|
|
