What is macular degeneration?
Macular degeneration is a term used for over 1500 conditions which affect central vision. Sharp, clear central vision is processed by the macula (also sometimes called the fovea) which is the central part of the retina and is about the size of a grain of rice. Macular degeneration (MD) occurs when the layer of the retina responsible for nourishing and carrying away waste products, starts to function less effectively as it ages. Cells in the macula break down, causing a gradual or sudden loss of sight in the central part of vision but leaving the peripheral vision unaffected. Although people do not lose all their sight, reading, recognition of faces, watching television and driving are very difficult or impossible.
What are the different types of macular degeneration?
Macular degeneration is classified as either dry or wet. The dry form is more common than the wet (about 87 percent of patients). In dry MD, the cells of the macula decay and disintegrate and cause loss of vision without turning into the wet form of the disease. However, it is also possible for early-stage dry MD to suddenly change into the wet form. The second form, wet MD, is more aggressive in its development. It is caused by the growth of abnormal blood vessels in the retina which can leak and lead to scarring and loss of central vision. There is no early or intermediate stage of wet MD; it is caused by abnormal fragile blood vessels growing behind the macula which leak fluid and blood causing rapid damage to the macula.
Is there a difference between macular degeneration (MD) and age-related macular degeneration (ARMD)?
Macular degeneration is usually age-related, affecting people over 65 years old, so the terms are often used interchangeably.
Can young people get macular degeneration?
Yes. There is an early onset macular degeneration (birth to age 7) that is genetic, called Best Disease or vitelliform macular degeneration. Macular degeneration (age 5 to 20) is also a genetic disorder commonly called Stargardt’s Disease, fundus flavimaculatus, or macular dystrophy. When people in their thirties or forties develop macular degeneration, it is also inherited and called Sorsby’s Dystrophy, Behr’s Dystrophy, Doyne’s Dystrophy, or Honeycomb Dystrophy. Finally, myopic macular degeneration can occur in people who are severely near-sighted due to extreme elongation of the eyeball. This condition can result in tears in the macula and bleeding beneath the retina.
Is Macular Degeneration Hereditary?
A gene has been found for a rare type of macular degeneration, but not for the kind that affects most people. Although it occurs in all races, it is more common in light skinned, blue eyed people.
What are the signs and symptoms of macular degeneration?
Early signs include: straight lines appearing wavy, fuzzy vision, and shadowy areas in your central vision. Our doctors may find indicators before you have any symptoms, so regular eye exams with an ophthalmologist are very important for an early diagnosis.
What is an Amsler grid used for?
One way to tell if you are having these vision problems is to view an Amsler grid. This grid consists of straight lines, with a reference dot in the center. Someone with macular degeneration may see some of the lines as wavy or blurred, with some dark areas at the center.
How is macular degeneration diagnosed?
Our doctors perform a dilated eye exam to view the back of the eye using a procedure called fundoscopy. If wet AMD is suspected, a fluorescein angiogram may be performed. This involves putting a dye into the bloodstream to see if the blood vessels are leaking.
Does macular degeneration usually affect both eyes?
Yes, although it may only be diagnosed in one eye, most patients are likely to develop it in their second eye as well. It is very important to monitor your vision and to report any deterioration to your doctor immediately.
What are drusen?
Drusen is a term for yellow deposits under the retina. They are an early common sign of dry MD. The risk of developing advanced dry MD or wet MD increases as the number or size of the drusen increases.
Can macular degeneration be treated?
There is no current treatment to prevent vision loss for advanced dry age-related macular degeneration. However, a specific high-dose formula of antioxidants and zinc may delay or prevent progression to the advanced stage. The wet form of the disease can be treated with photodynamic therapy PDT and injections into the eye.
What is Photodynamic Therapy (PDT)?
This therapy involves the injection of a light-sensitive drug into the patient’s bloodstream. The drug circulates throughout the blood vessels, including the abnormal vessels growing beneath the retina. A low-intensity laser is used to close the blood vessels to prevent further leaking of blood and fluid and to prevent the growth of more abnormal blood vessels. After PDT some occluded blood vessels may become incorporated into scar tissue. There can also be re-growth of abnormal blood vessels and these will require additional treatment. A course of PDT treatments over several months is often necessary. PDT is only approved for patients with wet macular degeneration. Vision already lost will not be restored by these techniques, but there are many low-vision aids that can help to alleviate the effects of loss of central vision.
Where can I find out about low vision aids?
There are many devices that help people with low vision function better. A starting point is to ask our doctors or optician.
Dr. Dale Stewart O.D. is our Low Vision Specialist. Please call 919.967.4836 ext 100 to schedule your Low Vision consultation today.
You may also contact the North Carolina Division of Services for the Blind.
Can visual hallucination be caused by macular degeneration?
Sometimes MD results in hallucinations and occurs in patients who have eye diseases that prevent the normal nerve impulses from reaching the brain. As the brain tries to interpret the signals it may generate spontaneous nerve activity which causes hallucinations called Charles Bonnet syndrome. It is estimated to occur in 12% of macular degeneration patients and appears more often in women than men. It is also more likely to occur if both eyes are affected by MD. The hallucinations are complex and fully formed images. They are most frequently of animals, writing, people or scenery. The hallucinations may last for seconds or for most of the day. They tend to disappear when people close their eyes. The syndrome may be experienced for days to years, although it usually disappears after a few months. People with Charles Bonnet Syndrome may need reassurance that that they are not “going crazy.”
I Heard about a new treatment for macular degeneration. What should I do?
Many scientists and doctors are looking for ways to treat macular degeneration. The media tends not to explain that most of these treatments are not tested to prove that they work. When considering any new treatment, you should ask:
- How many patients have been treated and how long have they been followed for side effects?
- What are the possible side-effects or second surgeries that may be required?
- Was this treatment proven to work by comparing it to either no treatment (observation) or another treatment?
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