- What is glaucoma?
- Who gets glaucoma?
- How is it diagnosed?
- How often should I be checked?
- Open-angle glaucoma
- Angle-closure glaucoma
- Glaucoma treatment
- Laser surgery
- Other surgery
What is glaucoma?
Glaucoma is a condition that occurs when pressure inside the eye (intraocular pressure) rises. The pressure is regulated by the balance between the amount of fluid the ciliary body of the eye produces and the amount that drains from the eye through the trabecular mesh work. When the drain becomes blocked or clogged, then the pressure rises. This pressure can crush the optic nerve, causing permanent vision loss, and sometimes blindness.
Who gets glaucoma?
It is not known what causes glaucoma. Many times glaucoma is an inherited condition, and therefore is more likely to occur in persons who have a family history of glaucoma. However, heredity is not the only factor in developing glaucoma. Other individuals at risk include persons who are over 35 years of age, very nearsighted, black or diabetic. Children can also get glaucoma.
How is it diagnosed?
The way your doctor tells if you have glaucoma is by measuring the eye’s pressure, evaluating the health of the optic nerve, and by testing peripheral (side) vision, where the first damage occurs. A visual field examination takes only ten minutes per eye, and is the best way to determine if vision has been affected.
How often should I be checked?
Because vision that has been destroyed by glaucoma cannot be regained, it is very important to detect glaucoma before much visual loss has occurred. Therefore, the key is early detection and regular eye exams. Your yearly eye exam should include a pressure check and evaluation of the optic nerve. If either result is unusual, a visual field should be done.
At 35 and 40, one should have a thorough glaucoma check. After 40, a thorough exam is needed every two to three years and every one to two years after 60. If one has an increased risk, a thorough check every one to two years should be done after 35. If glaucoma is diagnosed, visits may be needed more frequently.
Open-angle or chronic glaucoma is when the drain mesh work is not working properly. It is the most common form of glaucoma, affecting 2.5 million Americans. It is very dangerous because it rises so gradually that it causes no noticeable symptoms. There is no way of knowing if you have glaucoma unless you are examined regularly by an eye doctor.
There is no known cause for primary open-angle glaucoma, but many times it is inherited. Secondary open-angle glaucoma occurs in 5-10% of open-angle glaucoma cases and is the result of eye injury, inflammation, a tumor, or advanced cases of cataracts or diabetes. Open-angle glaucoma usually responds well to medications.
Angle-closure glaucoma is caused by a structural problem when the iris is pushed against the cornea, so fluid cannot get to the drain meshwork. An enlarged pupil, as in a dark movie theater or from certain medications, can cause iris to bunch up over the drain, forming a blockage. This type of glaucoma occurs in only 5-10% of glaucoma patients, primarily of Asian or Alaskan descent. A doctor can tell by a simple test if the angle is abnormally narrow.
Because angle-closure glaucoma occurs so quickly, it is also called acute glaucoma. It is noticed immediately because of symptoms of a red, painful eye, a halo around lights, and profound vision loss within hours of attack. One may experience extreme pain and even nausea or vomiting. If untreated, severe permanent vision loss and even blindness can occur in a few days. Therefore, it is important to receive immediate medical attention, day or night.
The treatment of glaucoma involves lowering the pressure by either decreasing the amount of fluid produced or by making the fluid drain better. Once diagnosed, it requires constant, lifelong care.
The first treatment is usually topical medication (eye drops), which must be taken regularly one to two times daily. Some can have side effects that include stinging or red eyes, blurriness, headaches, wheezing, heart rate changes, and mental fuzziness. However, these are uncommon. Over time, one’s medication may be changed so that tolerance does not develop. Your doctor will always prescribe the least amount of medication for the best results, with fewest side effects possible.
If the patient does not respond to medications, laser surgery may be an alternative. After the eye is anesthetized, a light beam heats up the drain meshwork, causing tiny areas to shrink and thus drain better. For angle-closure glaucoma, laser is used to make a small hole in the iris to act as the drain. It is painless for most and is successful in lowering the pressure in four out of five cases. Laser surgery only takes about 15 minutes, is done in the office, has a minimal risk of infection and complications, and special recuperation time is not needed. However, it is not for all patients, the results are not immediately known, the long term effects are uncertain, and most patients still need some medication after surgery. Laser surgery may not control glaucoma permanently, but may delay the need for microsurgery.
If previous treatments are not successful, microsurgery (filtering surgery) may be necessary. In this procedure, a tiny hole is made in the white part of the eye underneath the eyelid. This hole allows the fluid to bypass the clogged area and drain freely. In open-angle glaucoma, a piece of the iris is often removed. In some unusual cases, a plastic or silicone drain may be implanted in the eye to assist in drainage.
Microsurgery has immediate results, is generally successful and long lasting, and usually no glaucoma medication is needed afterward. However, there is some risk of hemorrhage, infections or complications, and the artificial drain can fail at a later date.
The procedure is done under local anesthesia and sedatives, and the patient experiences no discomfort. For at least a week, the patient must wear a patch to protect the eye and driving, reading, bending, and strenuous exercise must be avoided.
There is another procedure available where a freezing instrument or a special laser is used to inhibit the ciliary body that produces the fluid. But, it is performed only as a last resort, due to resulting inflammation.