What the eye doesn’t see

GLAUCOMA: DISEASE IS A MAJOR CAUSE OF BLINDNESS WORLDWIDE

If diagnosed early, permanent vision loss can be prevented.

Glaucoma is a disease that affects pressure within the eye, damaging the optic nerve. This leads to peripheral visual loss. Glaucoma is one of the leading causes of blindness worldwide, and 4 in 50 South Africans over the age of 40 suffer from it. It usually does not produce symptoms until vision is already severely damaged.

But if diagnosed early, the disease can be controlled and permanent vision loss can be prevented.

Glaucoma usually happens when fluid builds up in the front part of your eye. That extra fluid increases the pressure, damaging the optic nerve. Glaucoma may be inherited and may not show up until later in life. The increased pressure, called intraocular pressure, can damage the optic nerve, which transmits images to your brain. If the damage continues, glaucoma can lead to permanent vision loss. Without treatment, glaucoma can cause blindness within a few years.

Most people with glaucoma have no early symptoms or pain. You need to see your eye doctor regularly so she can diagnose and treat glaucoma before longterm visual loss happens. If you are over 40 and have a family history of the disease, you should get a complete eye exam from an ophthalmologist every two years. If you have health problems like diabetes or a family history of glaucoma, you may need to go more often.

Cause

Glaucoma is the result of high fluid pressure inside your eye. This happens when the liquid in the front part of the eye doesn’t circulate the way it should.

Normally, the fluid, called aqueous humor, flows out of your eye through a mesh-like channel. If this channel gets blocked, the liquid builds up. That is what causes glaucoma. The reason for the blockage is unknown, but doctors do know it can be inherited.

Less common causes include a blunt or chemical injury to your eye, severe eye infection, blocked blood vessels inside the eye, and inflammation. It does happen that sometimes eye surgery to correct another condition can bring it on. It usually affects both eyes, but it may be worse in one than the other.

Types:

Open-angle glaucoma: This is the most common type. Your doctor may also call it wide-angle glaucoma. The drain structure in your eye looks normal, but fluid does not flow out like it should. Angle-closure glaucoma: You may also hear it called acute or chronic angle-closure or narrow-angle glaucoma. Your eye does not drain right because the angle between your iris and cornea is too narrow. Your iris is in the way. This can cause a sudden build-up of pressure in your eye. It is also linked to farsightedness and cataracts.

Risk factors

It mostly affects adults over 40, but young adults, children, and even infants can have it. African-Americans tend to get it more often, when they’re younger, and with greater vision loss.

You’re more likely to get it if you:

Are over 40

Have a family history of glaucoma

Have poor vision

Have diabetes

Take certain steroid medications, like prednisone

Have had trauma to the eye

Symptoms

Most people do not have any symptoms. The first sign is often a loss of peripheral, or side, vision. That can go unnoticed until late in the disease. That is why glaucoma is often called the “sneak thief of vision.”

Detecting glaucoma early is one reason you should have a complete exam with an eye specialist every two years. Occasionally, pressure inside the eye can rise to severe levels. In these cases, you may have sudden eye pain, headache, blurred vision, or the appearance of halos around lights. If you have any of the following symptoms, seek immediate medical care:

Seeing halos around lights Vision loss

Redness in the eye

Eye that looks hazy (particularly in infants)

Nausea or vomiting

Eye pain

Tunnel vision

Diagnosis

Your eye doctor will use drops to open or dilate your pupils. He/ she will then check your optic nerve. The doctor may take photographs of the nerve to help him track your disease over time. Tonometry is a test performed to check your eye pressure. Visual field test, if necessary, is done to figure out if you have lost vision.

Treatment

Eye drops: These either reduce the formation of fluid in the eye or increase its outflow. Side-effects may include allergies, redness, stinging, blurred vision, and irritated eyes. Some glaucoma drugs may affect your heart and lungs. Be sure to tell your doctor about any other medications you are taking.

Laser surgery: This procedure can slightly increase the flow of the fluid from the eye.

It can stop fluid blockage if you have angle-closure glaucoma. Procedures include:

Trabeculoplasty: Opens the drainage area;

Iridotomy: Makes a tiny hole in the iris to let fluid flow more freely;

Cyclophotocoagulation: Treats areas of the middle layer of your eye to reduce fluid production;

Microsurgery: In a procedure called a trabeculectomy, the doctor creates a new channel to drain the fluid and ease eye pressure. Sometimes this form of glaucoma surgery fails and has to be redone. Your doctor might implant a tube to help drain fluid. Surgery can cause temporary or permanent vision loss, as well as bleeding or infection.

Open-angle glaucoma is most often treated with various combinations of eye drops, laser trabeculoplasty, and microsurgery. Talk to your doctor to find out which treatment is right for you.