It must be a frightening thing to realize that you are losing your vision. I, for one, tend to take normal vision for granted. How would I react if I started getting blurry vision or was unable to see parts of words as I read, or began to see people’s faces as grotesquely distorted? Well, I may find out. These are all symptoms of the most common form of severe vision loss in senior citizens: macular degeneration. Is it an inevitable consequence of aging? Once again, as with so many health conditions, there are steps we can take to decrease our risks. Let’s see what we can find out.
What is Macular Degeneration?
Macular degeneration is a chronic vision disorder that affects the macula of the eye, which is responsible for central vision. Individuals with macular degeneration may continue to have good peripheral vision, but progressively lose the ability to see what is directly in front of them. Typically, patients will experience blurry central vision or a blind spot in the center of their field of vision.
Macular degeneration is a relatively common condition, and is the leading cause of legal blindness in people over 60 years of age. Almost 30% of folks over the age of 74 are afflicted with some form of macular degeneration.
There are several types of macular degeneration. The most common form is called age-related macular degeneration (ARMD). It is estimated to affect about 10 million Americans. ARMD is also known as age-related maculopathy (ARM), or senile macular degeneration. There are two types of ARMD: dry (atrophic) and wet (exudative).
Maybe a short lesson on the anatomy of the eye will help us to understand macular degeneration better. The macula is located in the center of the eye’s retina, which is located on the innermost backside of the eyeball, closest to the brain. The macula, about 3-5 mm across, is responsible for central vision. Specialized light-sensitive cells called cones and rods compose the macula. The cones handle color vision, and the rods enable shades of gray. Both of these, particularly the cones, play a crucial role in healthy central vision.
Behind the macula, there are two structures that are important to understand in the discussion of macular degeneration (Pay attention class, there may be a quiz!). The choroid is a thin layer of blood vessels that primarily nourishes the cones and rods. Behind that is a layer called the retinal pigment epithelium (RPE). The RPE facilitates passage of nutrients from the choroid to the retina, and removal of waste products from the retina to the choroid. As we age, the RPE tends to become thinner and deteriorate. This interrupts the normal nutrition/waste removal cycles between the choroid and the retina. The cones and the rods begin to malfunction due to a lack of nutrients and excess waste products. Thus, they cannot communicate properly, and vision becomes blurred.
The dry form of ARMD constitutes about 85% of all ARMD cases. It progresses more slowly than the wet form, and it does not produce such severe vision loss as the wet form. Over time, the macula and the RPE begin to thin and deteriorate. The first symptom is usually blurry vision, and as the illness progresses, colors may fade or appear gray.
The wet form is usually a complication of dry ARMD. In fact, almost all wet cases start out as dry ARMD. It is called “wet” because it is characterized by the growth of new blood vessels in the choroid. Because the macula and RPE have already deteriorated to some degree, these new blood vessels may leak and cause blurred vision as well as other distortions. Patients with wet ARMD may see straight lines as wavy, and may develop a central blind spot. Wet ARMD often progresses very rapidly and produces more severe vision loss and distortions than dry ARMD.
There are also several other relatively rare types of macular degeneration:
- Cystoid macular degeneration: This occurs when cysts form on the macula and become filled with fluid
- Diabetic macular degeneration: Diabetics can get this form due to the breakdown of the macula from diabetes.
- Senile disciform degeneration: A severe form of wet ARMD that involves hemorrhaging of blood vessels near the macula. This is also known as Kuhnt-Junius macular degeneration.
What Are the Symptoms of Macular Degeneration?
Symptoms vary depending on whether one has wet ARMD or dry ARMD. However, the one common and defining symptom of any form of macular degeneration is a change in central vision. It may be blurriness or a blind spot, but it is always noticeable in central vision and not in peripheral vision. This is a major clue in determining macular degeneration. Remember that the symptoms of dry ARMD usually progress slowly, and they can sometimes be mistaken for ordinary symptoms of aging. Wet ARMD, on the other hand, typically progresses quickly.
Typical symptoms of dry ARMD include:
- The need for better lighting when doing close up work such as reading. This is often the first symptom that folks will notice.
- Blurry vision while reading
- Colors become less sharp and vivid
- A spot of blurriness or a blank spot in the center of your vision
- General haziness in overall vision
- Difficulty adjusting to changes in lighting, such as when walking into a dimly lit room
- Difficulty recognizing faces
Common symptoms of wet ARMD are:
- Distorted vision, such as angles appearing unusual, or things appearing smaller or farther away than normal, or straight lines looking wavy, and wavy looking straight
- Decreased acuity (sharpness or keenness) of central vision
- A blurry spot in the central vision
One symptom that deserves special mention is hallucinations. These may occur with any type of macular degeneration, but will usually not appear until the disease has advanced into the latter stages. These hallucinations may take the form of geometric designs, animals, or grotesque distortions of people’s faces. This can be very frightening to patients, and many are loathe to discuss them for fear of what others will think. Rest assured that if you have macular degeneration and are hallucinating, you are not developing mental problems on top of it.
What Causes Macular Degeneration?
There are certain risk factors that increase an individuals chances of developing macular degeneration. Some of these cannot be changed, but some of the major causes of this illness most definitely can be affected, as we will see in a moment.
Risks that cannot be changed are:
- Age: Being over 60 is a risk factor, as this is when the vast majority of cases are diagnosed.
- Heredity: Having a close relative with a history of macular degeneration increases the risk of developing it yourself. Researchers have identified some, but not all, of the genes that are linked to macular degeneration.
- Gender: Women are slightly more at risk than men. Women also may experience more severe effects, as they tend to live longer.
- Race: Macular degeneration is most common in Caucasians, especially past the age of 75. It is found less often in the Asian community, and is very rare in African-Americans.
- Light-colored eyes: Individuals such as this are more likely to get the illness than those with dark eyes.
Some risk factors can be lessened primarily by our diet and lifestyle choices. These are my favorite kind of risk factors, because they are choices we should be making any way to be proactive about our overall health:
- Smoking: Cigarette smoking doubles your chances of getting macular degeneration. This is the single most preventable cause of this condition.
- Diet: The cause of macular degeneration has been clearly linked to arteriosclerosis or “hardening of the arteries.” This is the same disease that causes most heart disease, strokes, and kidney disease in this country. A heart-friendly diet is also a deterrent against macular degeneration. Load up on lots of fruits and veggies, and stay away from saturated fats, animal protein, and processed/preserved foods. Eat whole, organic, and natural foods whenever possible. Antioxidants and minerals such as zinc are helpful in the diet as well. Of course, exercise is essential too. These are foundational to any health regimen, whether the concern is macular degeneration or any other health condition.
- Cardiovascular disease: If you have had a heart attack, or have high blood pressure, or a stroke, your risk for macular degeneration is increased. Eating and living healthily (as mentioned above) can reduce your risk of coronary disease, and as a bonus reduce risk of macular degeneration as well.
- Obesity: This is a factor in many diseases including macular degeneration. Applying healthy principles can avoid or manage obesity, and thus reduce the risk of macular degeneration.
- Exposure to sunlight: Excessive amounts of UV light, such as in sunlight, is thought to slightly increase the risk of macular degeneration. Wearing a quality pair of sunglasses should take care of this issue.
What Treatments are Available for Macular Degeneration?
Loss of vision cannot be reversed in any form of macular degeneration. Currently there are no known treatments for dry ARMD, but some intervention is possible for the wet form.
Time is of the essence when it comes to treating wet ARMD. The sooner the growth of the new blood vessels is discovered, the less damage they can inflict. These are a couple of the methods used to intervene:
- Photocoagulation: This involves the use of a laser beam that is aimed at the abnormal blood vessels in the choroid. These blood vessels are sealed off and destroyed to prevent further deterioration of the vision. This procedure is not appropriate for every patient. Whether it is used is dependent on the condition of the macula, the location of the blood vessels, and the quantity of blood that has leaked. Often the procedure will have some success, but it is disappointing to some patients. The progression of the disease may be stopped, but what appeared as a grey spot before, may now become a blind spot.
- Photodynamic therapy: This procedure is similar to photocoagulation, except it is used when the affected area is closer to the center of the macula where the sharpest vision is controlled. This method is less likely to damage the clarity of your vision.
One final thing I would like to mention is that often macular degeneration will affect only one eye, and the other eye can do an amazing job of compensating. As the disease progresses, some patients will also develop it in the other eye as well, but many people can go years by without experiencing severe symptoms due to this compensation factor. Perhaps this might encourage you or a loved one who is afflicted with this disease. Our bodies are truly amazing in their resiliency.