What is Glaucoma?
Glaucoma is a condition that may occur when pressure builds inside the eyeball. This pressure is called intraocular pressure (IOP). When the eye pressure is too high, it can damage the optic nerve. The optic nerve is like a “cable” with more than a million nerve fibers that send messages about what we see from the eye to the brain. These fibers join together to provide side vision, as well as sharp, central reading vision. As the increased pressure damages optic fibers, it cuts off the signals that the fibers send to the brain. Glaucoma can produce damage to these fibers causing blind spots to develop in areas of vision. People seldom notice these blind areas in the side vision until considerable optic nerve damage has occurred. If the entire nerve is destroyed, then blindness results. Fortunately, this seldomly occurs if glaucoma is diagnosed and treated before major damage has taken place.
The key to preventing optic nerve damage or blindness from glaucoma is early diagnosis and treatment. Comprehensive eye exams from your eye care specialist are the best defense against glaucoma. Several studies strongly suggest that lowering IOP may slow the risk of further progression of glaucoma.
What causes Glaucoma?
It is caused by a buildup of the fluid, the aqueous humor, which circulates within the eye. In glaucoma, the fluid drains too slowly out of the eye. As the fluid builds up, the pressure inside the eye increases. The aqueous flows through the eye contiuously. This flow can be compared to a sink with the faucet turned on all the time. If the drain pipe gets clogged, water collects in the sink. If the drainage system of the eye gets similarly blocked, the IOP increases and damage can occur. Unless this pressure is controlled, it may cause damage to the optic nerve and other parts of the eye.
What are the symptoms of Glaucoma?
At first, there are no symptoms. Vision stays normal, and there is no pain. In fact, 40% of your optic nerve can be damaged before you notice any vision loss. However, as the disease progresses, a person with glaucoma may notice his or her side vision gradually failing. That is, objects in front may still be seen clearly, but objects to the side may be missed. As the disease progresses, the field of vision narrows and blindness results. This is why glaucoma is often called “the sneak thief of sight”.
Who is at risk for Glaucoma?
Glaucoma poses an enormous public health problem. The government estimates that 2.2 million Americans have been diagnosed with glaucoma. Experts believe that nearly 2 million more may have the disease and not know it.
Age, race, and family history are all potential risk factors for glaucoma. But only your eye doctor can diagnose and treat this condition. African Americans over the age of 40 are at risk. Glaucoma is 6 to 8 times more common in this population. More than 1 out of 4 adults over the age of 50 have glaucoma or are at risk for glaucoma. There is a link between family history and glaucoma. If you have a parent or sibling with glaucoma, you have a 20% chance of developing glaucoma. Certain medical conditions also make it more likely to develop glaucoma. Diabetes and high blood pressure can increase your risk of getting the disease. If you are severely nearsighted or farsighted, you are also at risk. Past eye injuries also put you at risk.
Are there different types of Glaucoma?
There are several types of glaucoma. Open-angle glaucoma is the most common form of glaucoma and the one most often associated with aging. Closed-angle glaucoma is a condition in which fluid at the front of the eye can not leave because a part of the iris is blocking the angle through which it would flow. This type of glaucoma may result in a sudden increase in IOP, which is often accompanied by severe pain, nausea, and decreased vision and is considered a medical emergency. Congenital glaucoma is found in young people. This condition happens when children are born with defects in the angle of their eyes. These defects keep the fluid in the eye from draining. Secondary glaucoma can develop as a complication of eye surgeries, cataracts, inflammatory disorders, certain eye tumors, or eye trauma. Normal-tension glaucoma occurs when there is unexpected optic nerve damage in people who have normal IOP.
How is Glaucoma Diagnosed?
Glaucoma is detected through a dilated comprehensive eye exam. Your eye care specialist will exam your eyes for any optic nerve damage. They will also measure your IOP (intraocular pressure) by applanation tonometry. Additional examinations may include visual field testing, photography of your optic nerves, corneal pachymetry (thickness of the cornea), and ocular coherence tomography (thickness of the retinal nerve fiber layer at the optic nerve).
How is Glaucoma Treated?
High eye pressure is a major risk factor for glaucoma. It can be treated in 3 ways: medications, laser or surgery. Prescription eye drops are often used in the early stages of this condition. Some reduce the fluid produced by the eye, others help improve drainage. Because glaucoma often has no symptoms, you may be tempted to stop taking your medicine, or you may forget to take it. You need to use the eye drops as long as they help control your eye pressure. Regular use is very important. If the medications do not work, a type of laser can be performed to help the drainage of fluid from the eye. During laser surgery, a strong beam of light is focused on the angle where the fluid drains from the eye. If laser is not effective, a surgical procedure can be performed to also help drainage of fluid from the eye. Dr. Alexander will discuss and recommend which treatment is best for you.