Glaucoma is an eye disease that causes loss of sight by damaging a part of the eye called the optic nerve. This nerve sends information from your eyes to your brain. When glaucoma damages your optic nerve, you begin to lose patches of vision, usually side vision (peripheral vision). Over time, glaucoma may also damage straight ahead (central) vision. You may not notice a loss of side vision until you have lost a great deal of your sight. When checking for glaucoma, eye doctors usually look for damage to the optic nerve and any loss of side vision. They may also check your eye pressure. Glaucoma is often called the ‘silent killer’ because people usually do not notice any signs of the disease until they have already lost significant vision. Once lost, vision cannot be restored.
There are many types of glaucoma. The most common types include:
These risk factors may increase your chance of having glaucoma :
Your eye produces a watery fluid (aqueous humor), which goes into the eye and drains out. When your eye is healthy, the fluid drains through a mesh-like pathway and into the bloodstream. Aqueous fluid is produced by the ciliary body. It flows through the pupil and behind the clear cornea. Finally, it drains away through the trabecular meshwork. For some people, fluid can't drain properly because of a faulty drainage system. Drainage that once worked well may gradually slow down as you get older. A sink that becomes clogged backs up with water. When there is no place for excess fluid to go, pressure inside the eye builds up. This increased eye pressure may damage the optic nerve over time. Slowly, the nerve fibers that are essential for vision die. For others, glaucoma damages the optic nerve without increased pressure. These people may be unusually sensitive even to normal levels of pressure. Their glaucoma may also be related to problems with blood flow in the eye. Different people experience gla ucoma differently. Usually, glaucoma affects side vision (peripheral vision) first. Late in the disease, glaucoma may cause "tunnel vision." In this condition, the person can only see straight ahead. That's why someone with glaucoma can have good straight ahead (central) vision. However, even central vision can be seriously damaged.
Some people may need eye surgery to control their glaucoma. Lasers are very useful for treating glaucoma because they avoid cutting and have a lower chance of complications (compared to glaucoma surgery). There are three common laser procedures :
Creates a new path through the eye's tissues to let fluid drain from the eye. In the most common filtering surgery, called a trabeculectomy, the surgeon makes a small opening in the white part of the eye (the sclera) to create a new outflow path. The fluid then flows through the new opening and creates a bleb, which is like a small bubble or reservoir on the surface of the eye. The bleb holds the fluid while it is slowly absorbed into the surrounding tissue. The upper eyelid usually hides the bleb, so it's not noticeable to you or others. Most people who have this procedure no longer need medicine after surgery. Some people treated still need medicine, but they have better pressure control after the surgery. About 15 percent do not benefit from filtering surgery.
Drainage implant surgery is sometimes performed when a person is not suited for filtering surgery or when filtering surgery has failed. Depending on the kind of implant used, the surgery is called valve, shunt or seton surgery. In these procedures, the surgeon inserts a tiny tube through the sclera into the front part of the eye behind the iris. This tube becomes a path for fluid to drain away. The other end of the tube is attached to a tiny reservoir that acts like the bleb (described on page 19) to hold fluid until it is absorbed into the surrounding tissue. The reservoir is placed on the surface of the eye, back between the eye muscles, so it is not visible.
Even if surgery or drugs lower pressure in your eye, it's still possible to lose vision. Therefore you and your doctor must carefully monitor the disease. Since you will be visiting your eye doctor regularly, take time and care in choosing a person who you are comfortable with. Your doctor should understand that your questions and concerns are important. A doctor who is willing to work with you, listen to your concerns and provide the best treatment plays a large part in your success against glaucoma. You may need medicines every day for the rest of your life. Find support and encouragement from your family, friends and others. Sometimes it helps to talk to people who have experienced the same thing. It can help you to discuss side effects, share ways to remember your medicines and New medicines are being developed and other treatments may soon become available. Promising scientific discoveries will help you look forward to a bright future.