Although you may not hear about it as much as cataracts and retinal detachments, age-related macular degeneration (AMD) is the leading cause of severe vision loss in people over 50. AMD affects the small part of the retina (macula) that is responsible for our central vision. AMD can make it difficult or impossible for patients to perform routine activities such as reading and driving.
Macular degeneration is damage or breakdown of the macula of the eye. The macula is a small area at the back of the eye that allows us to see fine details clearly. When the macula doesn’t function correctly, we experience blurriness or darkness in the center of our vision. Macular degeneration affects both distance and close vision, and can make some activities like threading a needle or reading difficult or impossible. Although macular degeneration reduces vision in the central part of the retina, it does not affect the eye’s side, or peripheral, vision. For example, you could see the outline of a clock but not be able to tell what time it is. Macular degeneration alone does not result in total blindness. People continue to have some useful vision and are able to take care of themselves.
Many older people develop macular degeneration as part of the body’s natural aging process. The two most common types of age-related macular degeneration are “dry” (atrophic) and “wet” (exudative). Most people have “dry” macular degeneration. It is caused by aging and thinning of the tissues of the macula. Vision loss is usually gradual. Studies suggest that dry AMD is caused when white-yellow fatty deposits accumulate under retinal tissue.
“Wet” macular degeneration results when abnormal blood vessels form at the back of the eye. These new blood vessels leak fluid or blood and blur central vision. Vision loss may be rapid and severe. “Wet” macular degeneration accounts for about 10% of all cases of macular degeneration but 90% of severe vision loss caused by macular degeneration.
Macular degeneration can cause different symptoms in different people. The condition may be hardly noticeable in its early stages. Sometimes only one eye loses vision while the other eye continues to see well for many years. But when both eyes are affected, the loss of central vision may be noticed more quickly. A few common ways in which vision loss is detected is if words on a page look blurred, a dark or empty area appears in the center of vision, or straight lines look distorted.
The animation below provides an introduction to macular degeneration, its symptoms, and the dry and wet forms of macular degeneration.
Many people do not realize that they have a macular problem until blurred vision becomes obvious. Your ophthalmologist or optometrist can detect early stages of macular degeneration during a medical eye examination that includes viewing the macula with an ophthalmoscope and performing a simple vision test in which you look at a grid resembling graph paper. Patients over age 50 should receive a dilated eye exam at least every two years in order to allow for early diagnosis of macular degeneration.
Sometimes special photographs, called fluorescein angiograms, are taken to find abnormal blood vessels under the retina. Fluorescent dye is injected into your arm and your eye is photographed as the dye passes through the blood vessels in the back of the eye.
Despite ongoing medical research, there is no cure yet for “dry” macular degeneration. Some doctors believe that nutritional supplements may slow macular degeneration, and a research study sponsored by the National Eye Institute supports this theory. Treatment of dry macular degeneration focuses primarily on helping a person find ways to cope with visual impairment.
While there is also no cure for wet macular degeneration, several new treatment options have become available in the past decade years, and additional options are being researched quite aggressively. Treatment options currently available are listed below.
Using the Amsler grid
For patients at risk for macular degeneration – either due to family history, age or early signs of the disease – an eye doctor will often provide the patient with an Amsler grid. The Amsler grid is simply a piece of paper with a grid of straight horizontal and vertical lines that allows a patient to test their central vision each day (click here for to link to a printable Amsler grid). By using the grid, you may find changes in your vision that you wouldn’t notice otherwise. Putting the grid on the front of your refrigerator is a good way to remember to look at it each day.
To use the grid:
- Wear your reading glasses and hold this grid at 12-15 inches in good light.
- Cover one eye.
- Look directly at the center dot with the uncovered eye.
- While looking directly at the center dot, note whether all lines of the grid are straight or if any areas are distorted, blurred or dark.
- Repeat this procedure with the other eye.
If any area of the grid looks wavy, blurred or dark, contact your eye doctor immediately.
Treating wet AMD
Because ‘wet’ AMD is so serious, ophthalmologists will typically recommend treatment immediately. The most common treatment for wet AMD is the injection of anti-VEGF medications, and the two most popular anti-VEGF medications are Avastin and Lucentis.
Avastin and Lucentis are both produced by Genentech. Avastin was originally developed for the treatment of colon and rectal cancer, but practicing physicians discovered that Avastin also delayed the progression of wet AMD in these patients. Retinal specialists began using Avastin in earnest in mid- to late-2005, and it quickly supplanted other approaches (Visudyne and Macugen) as the most used wet AMD treatment. Eye injections represented an off-label use of Avastin since the drug was not approved by the FDA for wet AMD. However, the results with Avastin were so superior to other alternatives that most ophthalmologists felt they could not wait for FDA approval. The attractiveness of Avastin was two-fold: (a) it was more effective than other existing treatments and (b) the medication cost of $50 – $100 per treatment was far more attractive than the $900 – $1,300 cost for Visudyne and Macugen. The affordability of Avastin, even though not covered by all insurers, allowed many patients without insurance to finally receive treatment for their wet AMD. The out-of-pocket cost for each Avastin treatment at Midwest Eye Care is approximately $400.
In light of the success of Avastin, its manufacturer Genentech launched a clinical trial to gain FDA approval. However, Genentech submitted an Avastin derivative, renamed ‘Lucentis,’ for this clinical trial instead of the Avastin that was already commercially available for colorectal cancer. There is significant debate in the medical community about this relabeling, because it effectively allowed Genentech to justify a higher price for the wet AMD treatment while maintaining Avastin’s market share for colorectal cancer. The Lucentis medication has been priced at $1,995 per treatment, nearly 40 times higher than the cost of Avastin. Lucentis was approved by the FDA for treatment of wet AMD on June 30, 2006, and Midwest Eye Care began providing it to patients on July 17, 2006. The total cost for each Lucentis treatment is approximately $2,700, although many insurers will cover a portion of this cost.
Five years after Lucentis was introduced, there still has been no verdict on whether Avastin or Lucentis is more effective. The National Eye Institute, a division of the National Institutes of Health, began a research study in early 2008 to compare the effectiveness of each medicine. The study is still underway and preliminary results have not been reported. The website for the NEI/NIH study can be found by clicking here.
Retinal specialists may also use other treatments in conjunction with Avastin/Lucentis. The Visudyne therapy works well for some specific presentations of wet AMD, and kenalog and Triesence are injected steroids that reduces retinal inflammation to improve vision. There is no one right combination of treatments for all patients, so the retinal specialist must make these determinations based on the results of his or her exam and test results.
Aside from significant medical ethics debates regarding Genentech’s decision to increase the cost of this treatment by a factor of fifty, it does appear that Avastin and Lucentis currently represent the best treatments for most forms of wet AMD.
In its early stages, “wet” macular degeneration can also be treated with traditional photocoagulation laser surgery, a brief and usually painless outpatient procedure. Laser surgery uses a highly focused beam of light to seal the leaking blood vessels that damage the macula. Although a small, permanently dark “blind spot” is left at the point of laser contact, the procedure can preserve more sight overall.
In 2000, the FDA approved a treatment option for wet macular degeneration called Visudyne therapy. In this procedure, a light-activated drug known as verteporfin is injected into the bloodstream. Once the drug reaches the retina, it is activated by a non-thermal laser (a laser that does not burn the retina). This activation produces a clot that closes the abnormal vessels without causing damage to the overlying sensory retina. The abnormal blood vessels may return after several months. However, Visudyne therapy can be reapplied at up to three-month intervals if necessary.
The effectiveness of Visudyne for individual patients is not assured. In clinical trials preceding FDA approval, 46% of patients treated with Visudyne therapy lost less than three lines of vision (15 letters) on a standard eye chart compared to 33% of patients treated with a placebo. And when it came to severe vision loss, 70% of Visudyne patients lost less than six lines (30 letters) compared to 53% of placebo patients. Consequently, approximately 15% more patients treated with Visudyne were able to delay future vision loss compared to patients treated with a placebo.
Visudyne is only approved for certain types of wet macular degeneration, so a retinal specialist will determine if the therapy is appropriate for you. The retinal specialists at Midwest Eye Care were clinical investigators for the FDA Phase III trial of Visudyne therapy.
Verteporfin, the drug used in Visudyne therapy, is also used for chemotherapy and is quite expensive. While Medicare and most other insurers do cover the cost of the drug and the laser for specific indications, the patient may still have an out-of-pocket cost with this procedure.
Low vision training
Because no treatments are available for dry macular degeneration, and because the current treatments for wet macular degeneration will at best delay the loss of vision, patients may begin to lose their central vision after several years. However, total blindness is the exception rather than the rule.
Because side vision is usually not affected by macular degeneration, a person’s remaining sight can be very useful. Often, people can continue with many of their favorite activities by using low-vision optical devices such as magnifying devices, closed-circuit television, large-print reading materials, and talking or computerized devices.
Your eye doctor can also prescribe optical devices or refer you to a low-vision specialist or center. A wide range of support services and rehabilitation programs are also available to help people with macular degeneration maintain a satisfying lifestyle.
The National Eye Institute, an arm of the government-supported National Institutes of Health, coordinated the Age-Related Eye Disease Study, which followed the link between eye health and vitamin supplements for 4,700 patients over five years. The results of this study were first published in the October 2001 issue of Archives of Ophthalmology and are also available on-line on the NEI website.
Researchers found that patients who are at a high risk of developing advanced age-related macular degeneration (AMD) could lower their risk by about 25% when they were treated with high-dose combinations of vitamin C (500 mg), vitamin E (400 international units), beta-carotene (15 mg), zinc (80 mg) and copper (2 mg). The study also showed that people who have diets rich in green, leafy vegetables have a lower incidence of developing AMD.
This was the first study to show that vitamins can be an effective treatment in delaying the progression of AMD in people with intermediate or advanced disease. This approach is not a cure for AMD, nor will it restore sight already lost due to AMD. In addition, the study did not suggest any apparent benefits for patients who had no AMD or early-stage AMD, although we still recommend a multi-vitamin supplement for patients with early-stage AMD.
Within a few months of this study’s publication, many of the major pharmaceutical companies began selling vitamins consistent with the formulations used in this study. Widely-available brands include Bausch & Lomb’s PreserVision and Alcon’s ICaps vitamins. The AREDS researchers noted that this vitamin regimen is not recommended for all patients; for example, beta-carotene has been shown to increase the risk of lung cancer among smokers. Consequently, each manufacturer makes several variations of the AREDS formulation, so you should consult with your ophthalmologist or optometrist before beginning this therapy. For more information on the vitamin therapy, visit the National Eye Institute’s website at http://www.nei.nih.gov/amd/summary.asp#7.