Don't Get Blind Sided
Taking a closer look at Glaucoma
Glaucoma can’t be prevented nor can the damage caused by this silent thief of vision be reversed. But once diagnosed, it can be treated and further vision loss can be halted. Diagnostics testing is better than ever before, and safer treatments are increasingly available, says ophthalmologist Dr. Leonard Rappaport.
That’s good news for the approximately 2.2 million Americans who may have glaucoma, says Rappaport, of Tidewater Eye Centers, with offices in Chesapeake, Norfolk and Virginia Beach. As the Baby Boomers age, the number of people with glaucoma is expected to increase to 3.3 million by the year 2020. In the United States, 80,000–110,000 people are blind in both eyes because of glaucoma, Rappaport says.
High blood pressure in the eye, called ocular pressure, is the main culprit of the optic nerve damage caused by the most common type of glaucoma—open angle glaucoma, Rappaport says. Although the optic nerve damage can’t be reversed, it can be halted with treatment that includes drops, lasers and surgery, Rapport says.
Glaucoma is the leading cause of blindness among African Americans and is about four times more common than for people of European ancestry, according to The Glaucoma Foundation. Open angle glaucoma appears about 10 years earlier in blacks than in whites and progresses more rapidly, the foundation says.
People with advancing glaucoma gradually lose the edges of their peripheral vision—imagine watching a movie and gradually losing sight of the far edges.
“Glaucoma often is referred to as a silent disease or the sneak thief of sight,” Rappaport says. “The patient is not aware of the damage to the side vision. Only in the end stage when it starts to affect the central vision does the patient become more aware of it. At this point, it’s much more difficult to treat, and we can’t reverse any of the damage that has already occurred.”
With high blood pressure, you can adopt better habits—eat healthy, exercise more, lose weight—and probably see improvement. Unfortunately that’s not the case with high ocular pressure, says Dr. Sam Garrett of Virginia Beach Eye Center.
Instead, the first answer is early detection, Garrett and Rappaport say. Ophthalmologists now can detect glaucoma at early stages and begin treatment to preserve patients’ vision for the rest of their lives, Rappaport says. If you have a family history of glaucoma, you should get a yearly eye exam that includes a check for glaucoma, he says. Otherwise, you can go every three years, he says.
Your optic nerve has a built in safety margin—it’s possible to lose 40 percent to 50 percent of the optic nerve before the loss affects your vision, Rappaport says. “We like to detect the damage before it shows up on the visual field,” he says.
Ophthalmologists generally check your eye pressure on every visit. In children, a normal eye pressure is about 10, for adults it’s 15, and for seniors it’s about 20, Garrett says. As the number creeps higher, there’s more chance of optic nerve damage. The World Health Organization estimates that more than 100 million people worldwide have an eye pressure of more than 21, Rappaport says.
“The higher your ocular pressure, the more chance there is of having glaucoma,” Garrett says. “Someone with a pressure of 22 has a higher chance of getting glaucoma than someone with a pressure of 18.”
But not everyone with a higher than normal ocular pressure automatically has glaucoma, Garrett says. Ophthalmologists look for other signs of glaucoma including changes in your visual field, damage to the optic nerve, and differences between the optic nerve in each eye, he says. Doctors will follow more closely patients with higher than normal ocular pressure but no other signs of glaucoma, he says.
And it’s also possible to have glaucoma without having high ocular pressure, Rappaport says. This kind of glaucoma is called normal tension glaucoma and is more prevalent among Asian Americans, according to The Glaucoma Foundation.
In the United States, treatment of glaucoma usually begins with eye drops that lower ocular pressure, Rappaport says. But sometimes more than one kind of eye drop is needed and the doses may be different for each eye, depending on the level of optic nerve damage—making it tough for patients to comply with their regimen, he says. The drops also can have side effects that can make asthma and COPD worse, cause dry mouth and hasten detached retinas for patients who already are at risk for who already have a predisposition, he says. Plus, the medication is an ongoing expense.
Because of these issues, doctors in other countries are move more quickly to laser and surgical treatments, Rappaport says. The goal of laser and surgical treatments are to help drain the excess eye fluid that causes high pressure. Laser therapy can be done in the ophthalmologist’s office, he says.
The next step is incisional surgery. Depending on the technique, surgeons insert different kinds of tubes or shunts to allow fluid to drain, he says. Other techniques involve trying to get the eye’s existing drainage pathways to work again, Rappaport says.
“We’re trying to get as effective treatment for pressure lowering while minimizing any side effects to the patient and maintaining or improving the patient’s quality of life,” he says.