Macular Degeneration
What Is Macular Degeneration?
Macular degeneration is a general term that describes a degeneration or breakdown of the central part of the retina, called the macula.
Your retina is the light-sensitive tissue that is positioned at the back of the eye, where light rays are captured and transferred to the visual part of your brain via the optic nerve. The macula is a specific area of your retina that is responsible for providing you with sharpness, color vision, clarity and detail in your central vision (as opposed to peripheral vision). Macular degeneration is a generic term that is used to describe any type of breakdown, or ‘degeneration,’ of this specific area of the retina.
Breakdown of the macula is a potentially serious problem: you could suffer from distortion, blurriness, spotting, and hazing of your central vision. Patients who suffer from more advanced cases of macular degeneration could experience noticeable loss in their central vision and depth perception, making activities like reading and driving extremely difficult to accomplish.
It is important to note that macular degeneration only affects your direct, head-on vision, and does not affect your peripheral vision. So you could look at an object, such as a painting, and see the frame but not the actual image inside.
Age-Related Macular Degeneration (AMD)
Although there are several types of macular degeneration, the majority of people suffering from the condition developed it as part of the aging process. This is called age-related macular degeneration (AMD), and is a condition people need to be aware of and monitor as the sensitive tissues in our bodies breakdown as we age.
AMD is a serious condition, and is currently the leading cause of vision loss and blindness among Americans who are age 65 and older. Currently, there are about 10 million people in America who suffer from AMD. However, this disease is a growing problem, as the baby boomer generation that represents a large portion of the US population continues to age.
What Causes Macular Degeneration?
To date there are no know causes of macular degeneration, other than the disease being a symptom of the aging process. However, studies have shown that certain risk factors can strongly contribute to the development of macular degeneration, such as smoking, high cholesterol and uncontrolled high blood pressure. The disease also appears to be more common in Caucasians and females.
More importantly, recent studies suggest that there may be a genetic or hereditary component to the disease as well. This is exciting news because this discovery opens up the possibility for gene therapy and the development of more advanced treatment options to combat the condition.
Wet and Dry AMD
There are two forms of AMD that a person can be diagnosed with: “wet” (neovascular) and “dry” (non-neovascular). Dry AMD is the most common form of macular degeneration, making up approximately 90% of all cases of AMD.
"Dry" Macular Degeneration (Atrophic):
As mentioned earlier, this is the most common form of AMD. It is a result of the aging deterioration of the tissue that forms the macula. As this tissue ages and breaks down, it can form debris that gathers within the macula. This debris gathering begins to gradually affect the central vision of the person suffering from the disease. The process occurs rather slowly, with the patient suffering from central vision blurriness that gradually worsens over time. Although there is no cure, treatments and healthy habits can help slow the development of dry AMD.
"Wet" Macular Degeneration (Exudative):
In about 10% of cases, dry AMD progresses to the more serious and aggresive form of the disease, called wet AMD. Wet AMD is a result of the body developing abnormal blood vessels underneath the retina in an attempt to supply more blood to the damaged tissue of the macula. The problem is that these new blood vessels usually leak fluid or blood into the retina and blur central vision. With wet AMD, vision loss can occur very fast. One common symptom is the appearance of wavy lines where straight lines should be present. Wet AMD is a very serious disease that accounts for 90% of all blindness in the United States.
Some cases are treatable with laser surgery, and the administration of certain medications, both of which are done in the doctor's office. People suffering from the symptoms of wet AMD should seek treatment immediately.
What Are The Symptoms Of Macular Degeneration?
Macular degeneration affects everyone’s vision differently, so there is no one common set of symptoms. But the common thread is that since the condition affects your central vision, at some point you will notice changes in the way you visualize objects in your centralized field of vision.
Some of the more common signs of vision loss include:
- Difficulty focusing on words on a page or computer screen
- A dark spot or empty space might appear in the center of your sight
- Straight lines appear fuzzy, unclear or crooked
Most people hardly notice any vision loss at onset, and their vision continues to gradually worsen year after year, making the condition extremely difficult to detect. AMD also tends to affect only one eye at first, making it even harder to notices changes in your vision.
Macular degeneration alone does not result in total blindness. Even in more advanced cases, people continue to have some useful vision and are often able to take care of themselves. In many cases, macular degeneration's impact on your vision can be minimal.
Your physician can usually detect early signs of macular degeneration before symptoms occur. That is why it is important to maintain a healthy routine of vision checks with your primary vision provider.
How Is Macular Degeneration Diagnosed?
As mentioned earlier, most people suffering from AMD have trouble detecting any symptoms until more substantial vision loss has occurred. The good news is that your ophthalmologist (eye M.D.) can detect early stages of AMD, and begin preventative treatment before any noticeable vision loss has occurred. For people over the age of 60, a yearly eye exam is a must. Once you reach a certain age, your eye care physician will begin to administer specific tests to check for any early warning signs of AMD.
Some of these tests may include:
- An Amsler grid test, where you try and focus on special lines on a printed grid, searching for any visible areas of distortion
- Viewing your retina with an ophthalmoscope, searching for any abnormalities
- Performing a fluorescein angiography, where your doctor injects flurorescien dye into your bloodstream and then photographs the back of your eye
-An optical coherence tomography (OCT) exam, which is an imaging machine that can measure the thickness of your retina and visualize the microscopic anatomy
The greatest risk factor for AMD is definitely age, but the following groups of people have also been found to be more prone to the condition: women, whites, smokers and those whose immediate family members have had AMD.
The most important thing you can do to protect your vision from AMD is to have your eyes examined by an eye care professional at least once a year, particularly if you are age 60 or older.
How Macular Degeneration Is Treated
There is unfortunately no treatment that completely cures AMD, but several treatment options do exist that effectively slow the development of the disease. These treatments vary depend on how serious the condition is.
Treatment for Dry AMD
Research has shown that certain nutrients and supplements can slow the development of dry AMD. If you are suffering from symptoms of dry AMD, your eye doctor may recommend the daily use of the AREDS supplements, which is a special formula consisting of zinc, lutein and antioxidant vitamins (vitamin C, vitamin E and beta carotene). There is ample clinical evidence that shows high levels of antioxidants can slow down the progress of dry age-related macular degeneration. In smokers, high doses of beta carotene increase the risk of lung cancer and use of special formulations is indicated.
If you are currently suffering from dry AMD vision deterioration, low vision devices such as high intensity lights, magnifying glasses, and other devices can help you make the most of your visual situation.
Treatment for Wet AMD
For wet AMD, the treatment is targeted at either preventing the growth of new blood vessels, or the stoppage of leaking from the existing blood vessels.
There exist several medications that have been proven to slow the development of new blood vessels in the body. Two of the most common forms of this medication are Lucentis and Avastin.
Lucentis
Lucentis (ranibizumab) received FDA approval in late June 2006, for the treatment of advanced ‘wet’ macular degeneration. To date, it has been the most promising FDA-approved treatment for this condition that at one time meant certain blindness for patients.
Lucentis works by inhibiting proteins that stimulate the growth of new blood vessels in the body. The drug has been shown to effectively stop, and in some cases even reverse vision loss in most people with ‘wet’ AMD.
The medication is administered in the office by direct injection into your eye. This is a periodical and painless process process, requiring several treatments for maximum effect.
Avastin
There exists a less-expensive, non FDA-approved alternative to Lucentis, called Avastin. Avastin (bevacizumab) consists of a similar molecular makeup as Lucentis, with the only real difference being that the molecules in Lucentis are smaller than those of Avastin, which allow the drug to more effectively penetrate the retina.
Currently, Avastin is only FDA-approved for cancer treatment. But studies show similar effectiveness in the treatment of macular degeneration as Lucentis. Avastin is available off-label, and may be a better treatment option for lower-income families.
Laser Therapy
To stop the blood vessels from leaking, a patient may have to undergo laser therapy to destroy or seal off these new blood vessels. Unfortunately, recurrences after laser treatment are common. Laser therapy also subjects a patient to potential retinal scarring that can permanently leave blind spots in that patient’s vision.
It is important to understand that none of these treatments will dramatically improve your vision should you suffer from AMD. They are simply treatment options that can potentially slow the process of vision loss. The good news is that promising AMD research is currently being done. In the meantime, routine eye examinations with your primary vision provider are the most important steps to ensuring healthy vision.
To Learn More About Our Macular Degeneration Specialist:
Jaime Jiménez, M.D.
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