The leading cause of vision loss and blindness in Americans over the age of 65 is a disease called macular degeneration. The symptoms of the disease appear slowly and painlessly, but can be devastating to vision if left unchecked. There is currently no known cure for macular degeneration, though there are a myriad of treatment options available to prevent its slow progression, and even improve vision once the disease takes hold.
What Is Macular Degeneration?
Macular degeneration is defined as a disease that gradually destroys the central area of the retina, known as the macula. The macula transforms light waves from directly in front of the eye into nerve signals that the brain processes into discernable images. When the macula becomes damaged, crisp central vision is compromised. Macular degeneration, also known as age-related macular degeneration (AMD), slowly destroys central vision and, if left untreated, can seriously impair vision. Because macular degeneration affects only straight-ahead vision, it cannot lead to total blindness. It can, however, severely impair the ability of sufferers to easily perform normal activities such as reading and driving.
Causes of Macular Degeneration
Macular degeneration is a common eye disease in individuals over the age of 60. The causes of macular degeneration are unknown; however, environmental factors and genetics may contribute to this disease. The causes of macular degeneration have been associated with several risk factors, including:
- Age: People over the age of 50 are at a greater risk of age-related macular degeneration (AMD). While macular degeneration can develop in middle-aged people, chances of developing ARMD rise drastically with advanced age. In fact, age is the most telling risk factor for developing macular degeneration.
- Gender: Women are at a greater risk of developing macular degeneration.
- Race: Caucasians are more likely to develop AMD than African- Americans
- Smoking: Smokers are at greater risk of developing ARMD than non-smokers.
- Genetic history: Having family members who have suffered from ARMD increases the risk of developing macular degeneration.
- Cholesterol levels: Higher-than-normal levels of cholesterol may be correlated to a higher risk of developing the wet type of age-related macular degeneration.
The causes of the wet form of macular degeneration include aging, but severe nearsightedness and intraocular infections are also risk factors for this type of the disease.
Symptoms and Diagnosis
There are several different tests by which a qualified eye care physician can reach a macular degeneration diagnosis, each more or less useful for detecting different stages of the disease. Pupil dilation, the Amsler grid test, and fluorescein angiograms are currently the most effective ways to diagnose the disease. Read more about each type of macular degeneration test below.
Macular Degeneration Diagnostic Test
There are several procedures often used for macular degeneration diagnosis, each suited to test for different stages and forms of the disease. It is recommended that you see a specialist for a thorough diagnostic macular degeneration test and eye exam if you are over the age of 55 or are noticing any symptoms of macular degeneration.
During a standard eye exam, your eye care specialist may dilate your pupils to get a fuller view of the retina and a closer examination of any possible damage or debris. The patient’s eyes will be blurry for several hours after the test. A visual examination assisted by pupil dilation is one of the best ways to detect the early, or dry, form of macular degeneration. While detection of debris and decayed tissue in the eye does not necessarily mean that the patient will develop macular degeneration, the test is useful for determining whether preventative measures should be taken to defend against it. The earlier a diagnosis is made, the sooner you can begin treatment for macular degeneration.
Amsler Grid Test
One of the easiest methods for detecting macular degeneration is the Amsler grid test. The Amsler test is merely a square grid with black lines running parallel to each other horizontally and vertically, and a black dot in the center for the patient to focus on. A person with normal vision will see the grid as it appears on the page; however, a person with wet macular degeneration will see distortion in the lines, as if the grid has been twisted or has a hole in the middle of it. Early macular degeneration diagnosis may facilitate prevention of further vision loss, or even restore vision that has been lost.
If an eye care specialist suspects a patient is suffering from wet macular degeneration, he or she may order a fluorescein angiogram test. During the procedure, a special dye is injected into the bloodstream through the arm. Within seconds, the dye travels through the body to the eye. A special camera is then used to highlight the dye, allowing the eye care professional to see if there are leaks or problems in the eye — and, if so, where the problems are. While there are currently no treatments available to completely repair the eye after the onset of macular degeneration, catching it early enough may allow medications to prevent further damage or even restore some lost vision.
Progression and Types
Macular degeneration begins in the dry form, as the eye tissue begins to deteriorate and decay. As the name suggests, the disease advances as the tissue degenerates, progressively decaying over time. The wet, or neovascular, form of macular degeneration occurs when the body responds to this decay and attempts to replenish lost nourishment in the eye by creating new blood vessels. These blood vessels leak blood and fluid, causing permanent damage to light-sensitive retinal cells, creating blind spots. Approximately ten percent of dry AMD cases progress to the wet form.
As the disease progresses, patients may notice several changes in their vision.
Patients with the dry form of the disease may show no outward symptoms of macular degeneration. Deposits of drusen - formed from deteriorating tissue in the macula and other areas - can begin to accumulate in the eye without affecting a patient's vision. A qualified specialist can recognize these early symptoms of dry macular degeneration and suggest steps that may slow or halt its progression.
Blurry or Distorted Central Vision
As more and more tissue deteriorates in the macula and the rest of the retina, the patient may begin to experience blurry or shadowy vision, though the vision loss is not nearly as severe in the dry stages of the disease as in the later, wet stages. Patients experiencing macular degeneration progression should seek medical attention immediately, as there is still a chance that vision loss may be slowed, stopped, or even reversed slightly.
Complete Loss of Central Vision
The last (and most severe) phase of macular degeneration progression is the wet stage. During this phase, the body attempts to compensate for the deterioration of the macula by growing new blood vessels in the area. These blood vessels, and the blood and fluid that can leak from them, cause irreparable damage to the macula and resulting in a permanent loss of central vision.
Types of Macular Degeneration
There are a few different type of macular degeneration.
Age-Related Macular Degeneration
For people over the age of 60, age-related macular degeneration is the most common cause of severe vision loss. This disease affects an individual's central vision, which makes it difficult to drive, read, and complete several daily activities.
Age-related macular degeneration occurs when the center of the retina (the macula) degenerates causing the central vision to deteriorate. Rather than seeing the whole picture, an individual with age-related macular degeneration would see a dark or blind area in the central field of vision. Eventually, complete vision loss or blindness can occur.
Age-related macular degeneration is a scary possibility for many seniors as it could lead to greater dependence on others. However, there are several treatments available for age-related macular degeneration including medication and possible surgery. Many people can and have lived with this disease and educating yourself on the causes, symptoms and treatment will better prepare you if vision loss occurs due to age-related macular degeneration.
Dry Macular Degeneration
Approximately 90 percent of age-related macular degeneration sufferers have dry macular degeneration, an early stage of this disease. Central vision loss can occur with dry macular degeneration, however, it is not nearly as severe as it is in the wet form.
Though scientists are not sure what causes dry macular degeneration, they speculate that a part of the retina becomes diseased and leads to the destruction of the light-sensing cells in the macula. Aging and thinning of macular tissues can also lead to dry macular degeneration.
Advanced Wet Macular Degeneration
About 10 percent of people are affected with an advanced type of age-related macular degeneration known as wet macular degeneration. This form of the disease is more advanced and damaging than dry macular degeneration because it leads to the formation of new blood vessels within the eye that leak fluid and blood under the macula. This fluid leakage damages the macula and leads to vision loss in a short amount of time.
Wet forms of macular degeneration can be divided into two groups:
- Classic Wet Macular Degeneration: Associated with more severe vision loss. Occurs when growth of the blood vessels has clear outlines that can be seen beneath the retina.
- Occult Wet Macular Degeneration: In this type of advanced macular degeneration, leakage and growth behind the retina is not as evident, producing less severe vision loss.
Wet macular degeneration accounts for 90 percent of all blindness in age-related macular degeneration cases. Treatments such as surgery and medication are options for individual's that suffer from this advanced form of macular degeneration.
Treatment and Recovery
Macular degeneration treatment options vary greatly, with just as much variety in the type of recovery period one can expect following the procedure. Most treatments available now revolve around changes in diet and nutrition combined with drug therapy, making the recovery relatively simple. Some cases call for laser surgery, which is performed as an outpatient procedure with minimal recovery time. Learn more about macular degeneration treatment and recovery.
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