En español | If you've been diagnosed with the early stage of an eye disease, count yourself lucky.
Why? Because there are several million Americans out there who don't know they have one of the leading causes of blindness — glaucoma, age-related macular degeneration and diabetic eye disease. Our brains are so deft that they readily compensate for creeping loss of vision, masking early symptoms and putting us at risk of future blindness. By getting yearly dilated-eye exams, you allow your doctor to catch an eye disease early enough to begin effective treatment. You may be able to save your sight, and even reverse some of the damage.
But what if you're too busy to be bothered with annual dilated exams, or convinced your eyes are still performing at the top of their game? In that case, your future path might look very different. Many of us won't even see symptoms of an eye disease until it has progressed significantly. So if you want to see your grandchildren graduate high school one day, it makes sense to dedicate an hour or so every year to a dilated exam. The power is totally in your hands, and the difference is dramatic. Here's how four common eye diseases play out when you take action — and when you don't.
"Glaucoma has been called the silent thief of sight,” says Yvonne Ou, associate professor in ophthalmology at the University of California, San Francisco. More than 3 million Americans have glaucoma, but only half know it. The disease is marked by damage to the eye's optic nerve, which collects visual information from the retina and transmits it to the brain. At the beginning, one eye may lose more of its peripheral vision. “The other eye will compensate to cover up the problem,” says Ou, so with both eyes open you may not notice the vision loss.
If you take action: A comprehensive, dilated-eye exam is the best way to detect glaucoma. Every adult over age 50 should get this test every year, but if you have a family history of glaucoma, you may need one sooner or more often. “If we catch glaucoma early, it's a very treatable disease,” says Ou. “We tell patients with confidence that we can usually prevent vision loss that affects quality of life.”
The treatment goal is to reduce eye pressure, and that can be done via medicated eye drops or a laser procedure called selective laser trabeculoplasty (SLT). New research in The Lancet has found that, compared to eye drops, SLT is better at controlling pressure and can be more cost-effective, and fewer patients eventually require surgery. SLT is not a cure for glaucoma, but many patients find it far more convenient than drops.
If you don't: Glaucoma is extremely aggressive when it's diagnosed late or not at all. “When glaucoma is diagnosed late, the optic nerve is already damaged, and a damaged nerve is more vulnerable, so later-stage disease can be more difficult to control,” says Ou. With moderate to advanced glaucoma, you may find that important tasks involving the peripheral vision, like the ability to change lanes safely while driving, become challenging. The late stage of the disease affects your interior vision, so it can be tough to navigate stairs or curbs. Later stage glaucoma attacks central vision, and when left untreated, glaucoma can cause irreversible blindness.
Risk of sight impairment from glaucoma: 10 percent. Risk of blindness: 5 percent.
Age-Related Macular Degeneration
Eye Lingo 101
Retina: The layer of nerve cells lining the back wall inside the eye that senses light. The retina communicates with your brain to help you see.
Macula: An area in the center of the retina that helps you clearly see objects in front of you, like faces and written text.
Cornea: The window of the front of your eye that focuses light.
Optic Nerve: The nerve in the back of your eye that sends signals to your brain.
Dilation: A procedure during an eye exam in which drops are placed in your eye to widen your pupil, so the doctor can look inside your eye.
Legal blindness: When vision can’t be made better than 20/200 — meaning that you have to be 20 feet away or closer to see an object that someone with normal vision can see 200 feet away.
The biggest risk factor for developing age-related macular degeneration (AMD) is, well, your age. This progressive disease causes damage to the macula, the part of your eye responsible for fine central vision — critical for the tasks of daily living like facial recognition, driving, cooking or close-up work, says Mary E. Aronow, ophthalmologist at Massachusetts Eye and Ear in Boston. “It's a leading cause of vision loss in people over age 50 [and the leading cause of blindness in adults 65 and older]. The number of people affected is expected to more than double, from about 2 million to more than 5 million, by 2050,” she says. There are two types of macular degeneration: dry (involving a thinning of the macula, or center of the retina) and wet (when new, abnormal blood vessels grow under the retina, leak and cause scarring). Dry accounts for the majority of diagnoses.
If you take action: Doctors routinely look for AMD in patients over 50 during a dilated-eye exam. You may be told the disease is simmering under the surface, even if your sight seems fine. This is the best time to take action. “For dry AMD, we emphasize optimization of lifestyle,” says Aronow. Quit smoking is step one; after that the advice is to exercise regularly, get your blood pressure and cholesterol numbers in range, wear UV-blocking sunglasses, and eat a healthy diet, particularly fish and antioxidant-rich green leafy vegetables like spinach and kale. If your disease is already intermediate or advanced, you'll start taking dietary supplements called AREDS 2, which contains a specific mix of nutrients (vitamins E and C, copper, zinc, lutein and zeaxanthin) that have been shown in randomized clinical trials conducted by the National Eye Institute to slow the progression of AMD.
For wet AMD, treatment is with what are called anti-VEGF drugs, which help to stop bleeding and leaking from blood vessels in the eye. These medications are injected directly into your eye, something that sounds absolutely horrible, but don't panic: “The injections can be performed very comfortably; the thought of it is much worse than the reality,” says Aronow. The eye is numbed to promote comfort during the five to 10 minutes of treatment. You'll need these injections every four weeks initially, but over time the interval between injections will be spread out. “These injections can make a huge difference in the vision and quality of life in patients,” she says.
If you don't: As things advance, you may notice distortion in your vision — for example, straight lines can look wavy, says Aronow. Blurring in your central vision may develop. There is no cure for the disease, although “many people have stable or very slowly progressive AMD,” says Aronow. “Those with wet AMD can benefit greatly from anti-VEGF medications.”
Risk of early AMD progressing to advanced (wet) disease: 15 percent.
The number one reason you have cataracts: age. “By our 50s, we can usually start to see some changes in the transparency of the lens that are an indication of early cataracts. In some cases, cataracts can form at a much younger age, particularly for patients with certain conditions such as diabetes or autoimmune diseases, or people who have received steroids for a prolonged period of time for medical problems,” says Christian Klein, associate professor of clinical ophthalmology at UR Medicine's Flaum Eye Institute in Rochester, New York. Developing a cataract means there is a clouding in the lens of the eye, and while the condition is slow to progress, you may notice that glare makes night driving dangerous or that you can't read the small print on a menu or newspaper as you get into your 60s. Eighty percent of people with a cataract in the U.S. are white, according to the National Eye Institute. Half of white Americans have one by age 75. Hispanics are expected to have the biggest jump in cases, estimated to increase from 1.76 million in 2010 to 9.51 million by 2050.
When You Take Action: “When we see a cataract on an exam, it may take 10 to 20 years before a patient is bothered enough by them,” says Klein. At initial diagnosis, there's little your doctor can do to slow its progression. Treatment is cataract surgery.
Let your symptoms, and their impact on your life, be your guide as to when to take action. Your vision may be a stellar 20/20 on the eye chart, but if you have a cataract that causes significant life-impacting glare (for example, you have trouble getting to and from work), you are a candidate for surgery, says Klein. Cataract surgery has come far in the last 15 years: surgery is quicker (about six to 20 minutes in some cases), incisions are smaller and recovery time shorter (some people can go back to work that day), he says. In some cases, removing the cataract and installing a replacement lens restores vision so you can forgo wearing glasses. But the effects of the surgery can vary, and a good eye surgeon will never promise a particular result, says Klein.
If You Don't: Fortunately, things have changed from decades past, when doctors would wait until patients were nearly blind to take action (an outdated term called “ripening"). What's more, compared to decades ago, surgery no longer requires an extended hospital stay. However, if your cataracts are advanced but they don't affect your life in a major way, it's OK to wait. “Some patients are shocked by this, but we try to explain that cataracts are normal. Everyone gets them, it's just a matter of time,” says Klein.
Risk of moderate to severe visual impairment or blindness from cataracts: 13 percent.
Uncontrolled, elevated blood sugar damages blood vessels in the retina, causing a leakage of fluid into these tissues, a condition called diabetic retinopathy (DR). Because the retina is located in the back of the eye, you won't notice there's a problem with vision until it affects the center of the retina, which is what happens when the disease progresses. “Diabetes is a serious disease; you don't know that something is happening in your eye until it's too late,” says Majda Hadziahmetovic, an ophthalmologist and retinal specialist with Duke Health in North Carolina. More than 40 percent of Americans with diabetes have some stage of DR, according to the National Eye Institute.
When You Take Action: Duke Health has created a pilot program that automatically screens adult patients who have diabetes with an imaging test at their primary-care provider in order to detect the disease early. (Doctors recommend that everyone get a comprehensive dilated eye exam every year after age 50.) The early stage of the disease is called mild nonproliferative DR and, luckily, it can be controlled with lifestyle changes.
"The ball is totally in the patient's court, and we ask that they keep their A1c [a diabetes test result] below 6.5 with diet and exercise, as well as maintain careful regulation over blood pressure and lipid levels,” says Hadziahmetovic.
If You Don't: Diabetic retinopathy is the top cause of blindness in working-age adults in the U.S., according to the Centers for Disease Control and Prevention (CDC). Diagnoses of this eye complication are estimated to double from 7.7 million in 2010 to 14.6 million by 2050. Those who have diabetes are also more likely to develop cataracts at a younger age. The later, more symptomatic stage of DR is called proliferative, in which new, but weak, blood vessels grow in the retina to compensate for those that were damaged by blood sugar. When caught at this later stage — when symptoms like blurriness, or glare become noticeable — you may need a greater number of eye injections (to stop the formation of new vessels), laser treatments (to stop fluid leakage) or even surgery, to save your vision, says Hadziahmetovic.
Risk of diabetes leading to blindness: 25 times greater than the general population.