Age-related macular degeneration (ARMD) is the leading cause of legal blindness in those over the age of 65 years (1). Early ARMD currently affects more than 3.7 million Americans, with the number of new cases increasing rapidly due to increase in the number of elderly individuals. Risk factors include aging, gender (ARMD is twice as common in women as in men), systemic hypertension, smoking which increases risk of vision loss by 30-50%; light complexion and light-colored irides.
This course summarizes the pathophysiology of ARMD and presents a review of current strategies for its management. Age-related macular degeneration (ARMD) is a degenerative condition of the macula (the central retina). It is the most common cause of vision loss in the United States in those who are 50 or older, and its prevalence increases with age. AMD is caused by hardening of the arteries that nourish the retina. This deprives the sensitive retinal tissue of oxygen and nutrients that it needs to function and thrive. As a result, the central vision deteriorates.
Macular degeneration varies widely in severity. In the worst cases, it causes a complete loss of central vision, making reading or driving impossible. For others, it may only cause slight distortion. Fortunately, macular degeneration does not cause total blindness since it does not affect the peripheral vision.
Macula Degeneration Dry and Wet
Dry macula degeneration occurs in 90% of cases. There is a slow fragmented loss of the cells serving central vision rather like old paint flaking off a surface. The process continues over many years and is usually asymmetrical so that one eye preserves better vision than the other. Because the process is degenerative and dry, there is no inflammation to be suppressed or to form tight scars or fluid leakage to be sealed with the laser.
Wet macula degeneration only acounts for 10% of cases. However, because it has a more aggressive course, it accounts for 90% of the ARMD related legal blindness. “Wet” refers to leakage of fluid, serum or blood, at the normally dry perfectly aligned visual cell layer at the centre of the back of the eye, the macula. Fluid accumulation produces rapid visual blurring and shape distortion. This may be associated with low grade inflammation.
What is Wet AMD?
Wet AMD is a chronic, but treatable eye condition.
Wet AMD is caused by new abnormal blood vessels that grow and leak into back of your eye (the retina), making it harder to see.
Wet AMD affects the central part of the back of your eye (the macula) that lets you see sharply. It can affect your ability to read drive and recognize faces.
Wet AMD can progress quickly if left untreated and affect your everyday life like reading, shopping, driving and many more.
Wet AMD may appear to you as seeing wavy lines; blind spots (dark patches or empty spaces, which appear in the centre of your vision); or other changes in your vision.
Wet AMD is a chronic disease and most patients will need long-term treatment.
Macular Degeneration Causes
The exact cause of age-related macular degeneration (AMD) is unknown. Many studies have been done to identify AMD risk factors, however. The following are known to be, or strongly suspected of being, risk factors for age-related macular degeneration (AMD):
Age itself is a risk factor for AMD. In fact, people between the ages of 65 and 74 have a 1-in-5 chance of developing the disease. Over the age of 75, the chance increases to nearly 1-in-3.
Studies have shown links between cigarette smoking and increased risk of both “wet” and “dry” AMD. Current heavy smoking is associated with a 2- to 3-fold increased risk of AMD with vision loss.
Family history appears to play a role in AMD. Therefore, people with relatives with the disease should be especially vigilant about having their eyes tested. The American Academy of Ophthalmology (AAO) recommends that patients who have blood relatives with AMD have their eyes checked every 2 years.
According to the AAO, studies show that repeated exposure to the sun’s rays can contribute to eye disorders that commonly develop as we age, such as age-related macular degeneration (AMD) and cataracts.
Gender and Race
AMD is more common in women than in men. Whites are more susceptible to AMD than people of other races.
Poor nutrition can play a role in the development of common eye diseases. The good news is that, supplements containing antioxidants and zinc may reduce the risk of age-related macular degeneration (AMD) and vision loss.
Other Eye Diseases
Studies show that people with cataracts, glaucoma, and farsightedness have a greater risk of developing AMD.
Elevated serum cholesterol levels have been shown to increase the risk of AMD.
High Blood Pressure
Hypertension is also a risk factor associated with AMD, studies show.
What can be done to reduce the risk of developing AMD?
The role of vitamins, minerals, and antioxidants in the prevention of AMD was the subject of a National Eye Institute-funded study called AREDS (the Age-Related Eye Disease Study).
AREDS showed that people at high risk of developing advanced AMD reduced their risk of vision loss by 25 percent when they took high levels of certain antioxidants and zinc.
Because vitamin supplements were also shown to be effective with those intermediate AMD or with advanced AMD in 1 eye, the study demonstrated the importance of knowing your eye health status.
There are a number of vitamin supplements on the market today that are specially formulated to promote eye health and help prevent vision loss due to AMD and other diseases. Check with your doctor to see if supplements are an appropriate course of therapy for you.
Remember, the best way to ensure better eye health is through regular tests for glaucoma, cataracts, and, of course, age-related macular degeneration (AMD). So if you’re overdue for a visit to your eye care specialist, schedule an appointment soon.
Signs and Symptoms
Loss of central vision: This may be gradual for those with the dry type. Patients with the wet type may experience a sudden decrease of the central vision.
Difficulty reading or performing tasks that require the ability to see detail
Distorted vision (Straight lines such as a doorway or the edge of a window may appear wavy or bent.)
Macula Degeneration Tips
If you’ve been diagnosed with AMD, making a few simple lifestyle changes could have a positive impact on the health of your retina.
- Monitor your vision daily with an Amsler grid. By checking your vision regularly, changes that may require treatment can be detected early.
- Take a multi-vitamin with zinc. (Check with your eye physician for a recommendation). Antioxidants, along with zinc and lutein are essential nutrients, all found in the retina. It is believed that people with AMD may be deficient in these nutrients.
- Incorporate dark leafy green vegetables into your diet. These include spinach, collard greens, kale and turnip greens.
- Always protect your eyes with sunglasses that have UV protection. Ultraviolet rays are believed to cause damage to the pigment cells in the retina.
- Quit smoking. Smoking impairs the body’s circulation, decreasing the efficiency of the retinal blood vessels.
- Exercise regularly. Cardiovascular exercise improves the body’s overall health and increases the efficiency of the circulatory system.
Few tips to make reading easier:
- Use a halogen light. These have fewer glares and disperse the light better than standard light bulbs.
- Shine the light directly on your reading material. This improves the contrast and makes the print easier to see.
- Use a hand-held magnifier. A drugstore magnifier can increase the print size dramatically.
- Try large-print or audio books. Most libraries and bookstores have special sections reserved for these books.
- Consult a low vision specialist. These professionals are specially trained to help visually impaired patients improve their quality of life. After a personalized consultation, they can recommend appropriate magnifiers, reading aids, practical tips, and many resources.
- Use a bright reading light
- Wear your reading glasses if appropriate
- Hold the chart approximately 14-16 inches from your eye
- Cover one eye
- Look at center dot
- Note irregularities (wavy, size, gray, fuzzy)
- Repeat the test with your other eye
- Contact ophthalmologist if you see any irregularities or notice any changes