The Silent Thief
Early detection of glaucoma is vital.
High pressure can conjure varied images, from sweaty palms to hypertension to meteorological predictions of sunny skies (some of us will never forget Granite State weatherman Al Kaprielian's zany squeals of "High Preshah!").
If your eye doctor is talking to you about intraocular high pressure, pay serious attention. Glaucoma, the second leading cause of blindness worldwide, is most often brought on by high pressure within the eye. The precise mechanisms that trigger glaucoma are still not fully understood, but experts believe that fluid build-up within the eye causes damage to the optic nerve, which houses fibers that carry visual images from the eye to the brain.
Sometimes called the silent thief of sight, glaucoma is stealthy. It can come in different forms, but most commonly, it slowly and gradually damages the optic nerve, leading to irreparable vision loss that initially, the patient does not notice. In fact, an estimated 4 million Americans have glaucoma, but half do not realize that they have it, according to the Glaucoma Research Foundation. It doesn't typically hurt or have symptoms that patients are immediately aware of, says Sonalee Desai-Bartoli, M.D., M.P.H., an ophthalmologist and glaucoma specialist at Nashua Eye Associates. Glaucoma at first constricts peripheral or side vision, and, left untreated, can continue to shrink the visual field until all sight is lost.
Be on the lookoutAlthough there is no cure for glaucoma, doctors can slow or stop the progression of the disease, limiting the loss of vision. Early diagnosis depends on patients having regular eye exams, Desai says. During the exam, doctors can use various methods to check the pressure of the eye, including tonometry, a simple procedure that involves numbing the eye with drops. If they suspect that something might be awry, doctors can also employ a visual field machine to determine if a patient's peripheral vision has been damaged, and take special digital photographs of the back of the eye so that changes over time can be monitored, Desai says.
To properly guard against glaucoma, patients should be sure to have comprehensive eye exams that include pupil dilation and evaluation of the optic nerve, says Andre A. d'Hemecourt, M.D., an ophthalmologist and glaucoma specialist at The Eye Center of Concord. Screenings that only measure ocular pressure are "not enough," he says. "A good percentage of the people who develop glaucoma never get high pressure," he says, "so screening just by measuring pressure is not adequate." Measuring eye pressure is important and will flag some cases of glaucoma, but "a thorough examination of the eye, particularly the optic nerve, is the key" to prevention, he says.
As a rule of thumb, any patient over the age of 40 should have regular eye exams, Desai-Bartoli and d'Hemecourt say. Although glaucoma can strike at any age, it most commonly afflicts individuals who are middle-aged or older. Besides high ocular pressure and advanced age, risk factors include a family history of glaucoma. "There's a definite family tendency, a strong inheritance pattern [to glaucoma]," d'Hemecourt says, "so a person with a family history of glaucoma, particularly if their parent has significant glaucoma, should be getting eye exams," and so should that individual's children and grandchildren, he says.
TreatmentTreatments for glaucoma include medications, eye drops, laser treatments, and traditional surgery, all of which can help lower ocular pressure, either by enhancing drainage or reducing the production of fluid in the eye. "Usually by lowering the pressure about 30 percent we're able to prevent the progression of the disease," Desai-Bartoli says.
Lowering the pressure by about a third is the common plan of attack even for patients with normal pressure, d'Hemecourt says. "So if a patient has a normal pressure and they have glaucoma, you try to get it to a subnormal level. Statistics and studies show that even with people who don't have high pressure but have developed glaucoma, getting the pressure low is effective," he says.
Under pressureWhile it's true that patients with normal pressure readings can develop glaucoma, high pressure and glaucoma risk are clearly linked. So, how concerned should you be if your doctor tells you that you have high pressure? "Just having high pressure doesn't mean you have glaucoma," d'Hemecourt says. There's a lot of variation in what our bodies can tolerate, he says, and one person's ocular pressure threshold might be different than another's. "People worry when they hear that their pressure is high, but maybe for that person, that's fine," d'Hemecourt says. Since what amounts to damaging pressure in one person is not necessarily a problem in the next, doctors rely on comprehensive exams and diagnostic tools like the visual field test to determine if pressure in a particular individual is harming the
Don't be left in the darkSince early detection of glaucoma plays a vital role in saving sight, taking preventive steps is a smart idea.
For starters, it doesn't hurt to get moving. Nutrition and exercise are not directly related to glaucoma risk, experts say, but "potentially anything you can do to improve your overall circulation and your vascular health can help prevent glaucoma," Desai-Bartoli says. "Regular exercise may help improve your circulation and that may help protect your optic nerve."
After all, "glaucoma is not just a disease about pressure, it's also about the health of the optic nerve," Desai-Bartoli says. "We're interested more in your overall circulation and overall good blood flow to the optic nerve to help slow down the progression of glaucoma." Since pressure in the eye can affect the blood flow and nutrition supply to the optic nerve, most glaucoma treatments are pressure-centered, but the main goal is to enhance blood flow in that area, Desai-Bartoli says.
But while "generally good health that enhances your vascular status probably is helpful," d'Hemecourt says, full, routine eye examinations are the most critical safeguard against the threat of glaucoma. Lacking regular, thorough eye checks, a patient could be caught unawares. "What makes glaucoma such a difficult disease to deal with is, there really aren't any symptoms," d'Hemecourt says. "You don't feel that elevated pressure if it's there, and you don't see the loss of peripheral vision as it begins to close down on you until the very end. By then, it's almost too late." NH