Glaucoma

What is glaucoma?
Glaucoma is one of the most common causes of blindness in developed countries. It is characterized by optic nerve damage, an elevated intraocular pressure (although not necessarily), a reduction in peripheral vision, and eventually, if not treated, a loss of central vision. The cause is poorly understood, but many researchers feel it may be genetic. Since it is a chronic, silent disease, many people don’t even know they have it unless they visit an eye doctor for a comprehensive examination. Approximately 2.5 million Americans have glaucoma, but only one million are aware they have the disease.

Are there different types of glaucoma?
There are several types of glaucoma with open angle, closed angle, traumatic, and childhood glaucoma being the most common forms. All of these types have an abnormality of the eye’s drainage system. The eye pressurizes itself by producing a fluid known as aqueous humor, important for metabolic processes in the eye. There is a balance between how fast this fluid is made and how fast it drains out of the eye. This drain is located in an area of the eye known as the angle. Open angle glaucoma is the most common form accounting for 70 percent of all cases. Although the "drain" is open, there appears to be a clog in outflow: a back-up of fluid pressure is transmitted to the optic nerve, which gradually causes damage to it. Closed angle glaucoma accounts for 10 percent of all glaucoma and is characterized by complete closure of the angle preventing any fluid from leaving the eye, and the intraocular pressure may rise rapidly to high levels and damage the optic nerve. In childhood glaucoma, the angle may have developed abnormally and results in a "developmental clog" which does not allow fluid to drain properly, thereby increasing the pressure in the eye. Similarly in secondary causes of glaucoma, for example trauma, the drainage system is affected.
Despite the importance of intraocular pressure, other factors seem to play a role in glaucoma. In fact, researchers feel that glaucoma is a multi-factorial process involving not only pressure, but also blood flow, genetic expressions of faulty enzymes or proteins, and spontaneous degeneration of the optic nerve itself.

Who is more likely to get open-angle glaucoma?
Average normal pressures are between 10-21 mm. Hg. Patients with intraocular pressures greater than 21 mm.Hg. run a three to five percent chance of having glaucoma. The older the patient, the higher the risk; it is approximately 0.1 percent in people 40-54 years old and 2-7% for those over 70 years old.

Race is another major risk factor. African-Americans are three to four times more likely to suffer from glaucoma than are Caucasians. It is not only more prevalent among African-Americans than Caucasians, but it also may occur at an earlier age and be more advanced when diagnosed. Other potential risk factors for primary open-angle glaucoma include a family history of glaucoma in immediate relatives, such as siblings or parents, possibly myopia, and possibly a history of hypertension or diabetes.

Is glaucoma curable and how is it treated?
There is no cure for glaucoma. If left untreated it will cause complete blindness; once damage is done and visual loss occurs there is no way to regain it. But if treated in time, all vision loss can be halted, and glaucoma patients can keep the vision they have at the time treatment is started. The treatment goal is to reduce the intraocular pressure and protect the optic nerve from further damage. The objective is to slow the course of the disease in order to maintain useful vision for as long as possible and in certain instances arrest its progression.

The most common treatment is eye drops instilled into the eye every day. There are several types of anti-glaucoma medications (drops). Some are designed to reduce the amount of fluid produced in the eye and others are designed to increase the drainage of fluid. Many times a combination of medications are necessary to reduce the intraocular pressure to a good level. Anti-glaucoma pills are also prescribed, if necessary, but they have side effects that may limit their use. Unfortunately, these medications have to be continued indefinitely to be effective, just like pills for high blood pressure or medicine for diabetes. If the medications are stopped, the intraocular pressure will rise back to its original level, and the disease may worsen.

Constant monitoring is key for effective treatment. Your eye doctor may need to see you every three to four months to check the pressure and to examine your optic nerve as the medicine may lose its effect. Peripheral vision is tested with the use of a visual field machine, and the optic nerve can be measured with other sophisticated instruments to be sure it is remaining healthy. These tests also provide baseline information that may be compared from year to year to judge the progression of disease. If your visual field is worsening, your eye doctor will become more aggressive in your treatment.

What happens if the drops or pills don’t work to control my glaucoma?
There are times when patients do not respond to medications or become intolerant to them. Consequently, laser surgery is required. Laser is a light source that is applied directly to the drain in order to stimulate the exit of fluid. It acts as "Drano" to a clog and is referred to as laser trabeculoplasty. It is a painless and simple procedure which the physicians at CEENTA are trained to do. Laser trabeculoplasty is not a cure and sometimes has only a temporary effect; it can last several months or several years and may need to be repeated depending on the clinical course. Despite laser trabeculoplasty, patients still my have to use the medications as they did prior to laser. Only rarely do patients discontinue the medications. There are different types of lasers for other types of glaucoma as well.

In glaucoma, surgery is an option when other treatements fail or are not well tolerated. Presently, there are two types of surgery available, trabeculectomy and aqueous shunts. Both procedures are used to create a new drain to redirect fluid out of the eye, and can be used for all types of glaucoma. They are not without risks and are therefore usually not used as a first option. Some of the risks include hemorrhage, infection, or too low a pressure. These risks are rare but can cause loss of vision if they occur. Fortunately, most times the results are good, and the pressure can be maintained at a low healthy level for many years often without the additional use of drops. Continuing refinements in surgical technique are improving our results. The board certified physicians at CEENTA are all experienced and capable of tailoring a treatment plan for individual patients with glaucoma. Our glaucoma sub-specialists have vast experience in glaucoma surgery and treatment. Trabeculectomies and aqueous shunt procedures are done more regularly within our group than anywhere else in North and South Carolina.