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Macular Degeneration Diagnosis and Treatment from Our Richardson Optometrists
What is the Macula?
The macula is situated at the center of the sensory retina, which lines the back surface of the eyeball much the same way that wallpaper adheres to a wall. It is the leading cause of vision loss over the age of 60. The retina contains rods and cones, the cells that transduce light into neural signals that eventually travel to the visual cortex of the brain. The macula contains the highest concentration of cones, which are responsible for color and detailed central vision. People use central vision to perform tasks such as reading, driving, and anything else that requires sharp acuity.
What is age-related macular degeneration (AMD)?
AMD is a common eye disease that gradually destroys the macula leading to a degradation of sharp, central vision. In some patients, age-related macular degeneration advances so slowly that it will have little effect on their vision in the early stages. But in others, the disease progresses faster.
How does AMD damage vision?
By causing a breakdown of the macula cells, age-related macular degeneration affects the central vision that is necessary for reading, driving, identifying faces, watching television, doing detailed close work, safely navigating stairs and performing many daily tasks. It rarely causes total blindness, as peripheral vision is usually not affected.
AMD occurs in two main forms: wet and dry.
What Is Dry AMD?
This is the most common form of AMD, affecting 85% of people who have the condition. In the dry form, the underlying cells that provide support and nutrition to the macula begin to break down and this disrupts normal macular function leading to reduction of central vision and color perception. Generally, the damage caused by dry AMD progresses slowly however patients with dry AMD are susceptible to developing wet AMD.
What Is Wet AMD?
This is the more severe type of age-related macular degeneration. Although it affects only 15% of those who have macular degeneration, 90 percent of blindness resulting from AMD is from this form of the disease. In wet AMD a membrane underlying the retina thickens, breaks and disrupting nutrient and oxygen supply to the macula. The body responds to this lack of oxygen by growing new blood vessels in an attempt to restore adequate flow. These new, fragile blood vessels do not function well in that they leak blood, fluid, and fats and can detach the macula. This process also causes scarring, resulting in rapid central vision loss.
Who is most likely to get AMD?
The greatest risk factor is age. Although AMD may occur during middle age, studies show that people over age 60 are clearly at greater risk than other age groups.
- Other Age-Related Macular Degeneration risk factors include:
- Gender–Women tend to be at greater risk for AMD than men.
- Race–Caucasians are much more likely to lose vision from AMD than African Americans.
- Smoking–Smoking significantly increases the risk of developing AMD.
- Family History–Those with immediate family members who have AMD are at a higher risk of developing the disease.
What are the symptoms of AMD?
Both dry and wet age-related macular degeneration cause no pain. The most common early sign of AMD is blurred or distorted vision. As fewer cells in the macula are able to function, patients with AMD will see details less clearly, such as faces or individual words in a book.
Another classic early symptom of both wet and dry AMD is that straight lines appear crooked. As AMD progresses, patients notice an enlarging blind spot in their vision.
Central vision loss of rapid onset can be a sign of wet AMD. Any noticeable change in vision necessitates contacting Drs. Stokol and Associates immediately.
Here are some examples of what a patient with macular degeneration might see. Figure 1 shows the typical wavy lines at the center of vision. Figure 2 shows the missing image that is characteristic either of wet macular degeneration or of the later stages of dry macular degeneration.
How is AMD detected?
To look for signs of the disease, Drs Stokol and Associates use high magnification lenses to study the macula after the pupils have been dilated. Viewing an Amsler grid, a pattern that looks like a checkerboard, also provides important diagnostic data. Early changes in central vision will cause the grid to appear distorted. Below is an example of an Amsler grid. Hold the grid at 33 cm while covering one eye and look at the dot in the center of the grid. Keep staring at the center dot, and if while doing this, the lines around the dot appear wavy or distorted, schedule an appointment to see either Dr. Stokol or his Associates. DO NOT rely on this grid alone for a diagnosis. The only way to determine the presence or absence of age-related macular degeneration is to have a thorough examination by our doctors or by a retina specialist.
The following graph depicts the appearance of an Amsler grid to a patient who has Age-Related Macular Degeneration.
How Can AMD Be Treated?
There is no treatment presently for dry age-related macular degeneration, although use of antioxidant vitamins may slow its progress. Please see our ‘Vitamins and Your Vision’ section for an in depth discussion on the role of vitamins and nutrition in eye care.
Surgeons treat some cases of wet age-related macular degeneration with lasers however more recently injections of new the new drugs Avastin and Lucentis have proven to be more effective in controlling wet AMD.
What Can I Do To Protect My Vision?
Dr. Stokol supports the notion that AMD has a vascular (blood flow) component. As the macular is so packed with visual cells (cones) it does not have its own blood supply and relies on the choroid for its nutrients. Any reduction in blood flow to these delicate choroidal vessels due to cardiovascular insufficiency will affect macula health. In order to maximize peripheral blood flow follow a health regimen that is good for the heart. We recommend the following steps:
- If you are a smoker, STOP SMOKING IMMEDIATELY! Smoking constricts the peripheral arteries and smokers are known to have low levels of lutein, putting them at greater risk of developing macular degeneration than nonsmokers.
- Control high blood pressure. The link between high blood pressure and AMD is well established. If you have high blood pressure, keep it under control by following your internist’s advice.
- Protect your eyes from exposure to harmful sunlight. Ultraviolet light and blue light can damage your retina and may increase your chances of developing macular degeneration. It is extremely important to protect your eyes when you are outdoors by wearing a hat or visor, even on overcast days. Ultraviolet light passes through cloud cover and is just as dangerous as direct sunlight. Wear good quality sunglasses that screen 99-100% of ultraviolet A and B rays as well as blue light (the short wavelengths). Many sunglasses are mislabeled and therefore at our optical, we take great care to carry only high quality sunglasses that provide maximum protection.
Clear glasses can also be treated with ultraviolet filters. This is a clear coating that will not interfere with your sight. We would be happy to discuss clear and sunglass options for you. Ask to speak to one of our opticians.
- Eat a healthy diet and engage in regular cardiovascular exercise. A healthy heart increases the blood flow to the capillaries that nourish the macula.
- Limit alcohol consumption to just a few drinks a week. Limiting alcohol improves circulation, vascular health (and liver health).