Glaucoma is one of the leading causes of blindness in the United States. Glaucoma is a general term for a family of eye diseases that damage the optic nerve. The optic nerve is located in the back of the eye and relays information from the eye to the brain.
Elevated pressure inside the eye creates stress on the optic nerve. If the optic nerve is damaged, vision loss occurs. In most cases, glaucoma has no pain or other symptoms until noticeable vision loss is present.
Warning Signs and Symptoms
Open-angle glaucoma is the most common form of glaucoma in the United States and has no initial symptoms. Known as the “sneak thief of sight,” open-angle glaucoma develops slowly over time. The disease begins when the drainage canals of the eye become clogged which elevates the internal pressure of the eye. This increase in pressure damages the optic nerve, but you may not experience any changes in vision until severe eye damage has already occurred. The two major symptoms of open-angle glaucoma are an altering of peripheral vision and tunnel vision (in the advanced stages).
Acute closed-angle glaucoma is the result of a sudden blockage in the normal flow of eye fluid between the iris and the lens. This occurs when the iris is not as wide and open as it should be. The outer edge of the iris blocks the drainage canals when the pupil enlarges too much or too quickly. This results in a sudden rise in intraocular pressure. Symptoms include severe pain, nausea, vomiting, blurred vision, eye redness, sudden onset of visual disturbance in low light, and seeing a rainbow halo around lights. These symptoms are intense and noticeable, and you must get medical attention immediately.
Congenital Glaucoma is a rare type of glaucoma that affects infants at birth. Some children can also get a type of this disease
Who is at Risk?
Your risk for glaucoma increases after the age of 40. African Americans are more likely than Caucasians to be diagnosed with glaucoma. Other risk factors include:
- Eye injury
- Eye tumor
- Use of corticosteroids
- Family history of the disease
Your doctor may perform several tests to diagnose glaucoma. Most glaucoma is diagnosed through a routine pressure check, using tonometry that is part of a comprehensive eye exam. Your doctor may also check for optic nerve damage by looking directly through the pupil at the back of your eye to examine the shape and color of the optic nerve. Slight changes in the optic nerve may indicate the presence of glaucoma. A visual field test can diagnose whether your peripheral vision has been affected by glaucoma. Your doctor may also measure the thickness of your cornea because corneal thickness can affect intraocular pressure. Finally, your doctor may examine the angle in the eye where the iris meets the cornea to see if it is closed and blocked or wide and open.
Treatment and Procedures
Damage to the optic nerve is irreversible, so there is no cure for glaucoma. Therefore, it is imperative to have regular checkups and take prescribed medication as directed. The objective of glaucoma treatment is to reduce intraocular pressure. This is done by improving the drainage of fluid in your eye or lowering the amount of fluid produced in the eye.
Medicated eye drops are the most common form of treatment. The medications work well for many people, but using eye drops is more complicated than most people realize. For eye drops to be effective you must use them every day or you can do more damage to your optic nerve. Sometimes your doctor may prescribe more than one type of drop. If this is the case, you should wait five minutes between each type of eye drop to receive the maximum benefit. You should also close your eyes for at least 30 seconds after administering the drops to keep all the medication in your eye.
If medicated eye drops are not sufficient, your ophthalmologist may suggest surgery. There are many different surgical options for treating glaucoma that usually depend on the type of glaucoma (closed-angle or open-angle).
Traditional Glaucoma Surgery Options
Trabeculectomy is a traditional surgery option that treats open-angle glaucoma and chronic cloased-angle glaucoma. Trabeculectomy, also called filtration surgery, is a surgical procedure to remove part of the trabecular meshwork in the eye to reduce pressure caused by glaucoma. Another traditional surgery option that is used when trabeculectomy is not effective is a tube shunt procedure called a glaucoma drainage device. Glaucoma drainage devices are designed to route fluid (aqueous humor) from the anterior chamber of the eye to an external reservoir. GDDs have been performed for about 40 years and have been improved for maximum success and IOP control.
Laser Glaucoma Surgery Options
There are also laser surgical options to treat glaucoma. Laser trabeculoplasty is often used to treat open angle glaucoma. This procedure uses a narrow, focused beam of light to open up the drainage angle of the eye. The surgery makes it easier for fluid to flow out of the front part of the eye, which lowers intraocular pressure.
For closed angle glaucoma, laser iridotomy may be recommended. The goal of this surgery is to decrease pressure in the eye and prevent a sudden buildup of pressure in the eye. Laser iridotomy uses a focused laser beam to create a small hole in the edge of the iris to allow fluid to flow between the front of the eye (anterior chamber) to the area behind the iris (posterior chamber).
Emerging Glaucoma Surgery Options
There are a number of new, emerging surgical treatment options for glaucoma as well. Mini glaucoma shunt surgery is an alternative to a larger silicone tube shunt or a repeat trabeculectomy. About the size of a grain of rice (3mm), the mini-shunt has a spur-like extension on one end and an external disc at the other. The shunt is a simple method of filtration for open-angle glaucoma and lowers IOP by routing aqueous humor from the anterior chamber of the eye.
Trabectome surgery is an option for patients who have both glaucoma and cataracts. Trabectome is a new, probe-like device that is inserted into the anterior chamber of the eye through the cornea and opens the eye’s drainage system.
The latest treatment option for patients with both cataracts and glaucoma is known as Micro-Invasive Glaucoma Surgery (MIGS). MIGS uses a microstent, about the size of an eyelash. A surgeon can open the eye’s drainage system during cataract surgery. Most patients with a cataract and open-angle glaucoma are good candidates for this procedure.
Talk to your doctor to see which one of these surgical options is best for you and will help preserve your vision.
There is no way to prevent open-angle glaucoma, but you can prevent vision loss from the condition. Early diagnosis and careful management are the keys to preventing vision loss. Most people with open-angle glaucoma have no symptoms. Everyone over age 40 should have an eye examination at least once every five years, and more often for anyone in a high-risk group, including people with a family history of open-angle glaucoma. Those 65 and over should have an eye exam every one to two years, or as recommended by your ophthalmologist.
Because eye injuries can cause glaucoma, it is important to properly protect your eyes when you use power tools or participate in active sports. Protect your eyes in the sun by wearing sunglasses and a hat and observe safety precautions to preserve your vision.
A moderate exercise program will benefit your overall heath and may help lower intraocular eye pressure. Studies show that regular, moderate exercise like walking or jogging three times per week can help reduce your eye pressure. It is unlikely that regular exercise will replace the eye drops or other glaucoma treatment, but it has a myriad of health benefits. Talk to your doctor about what kind of exercise regime is best for you.