Age-related macular degeneration (AMD) is a leading cause of severe vision loss and legal blindness in adults over 60 in the U.S. It affects 14-24% of the U.S. population aged 65-74 and 35-40% of people 75 and older3. Though AMD alone almost never causes total blindness, as peripheral vision is not necessarily affected, the loss of any amount of vision can have a huge impact on your life. As the population ages, it is estimated that the number of Americans with AMD will grow from approximately 2 to 5 million between 2010 and 20501.
What is Age-Related Macular Degeneration (AMD)?
AMD is a disease that blurs the sharp, central vision controlled by the macula, a small area near the center of the retina. You use central vision for “straight-ahead” activities such as driving a car, reading, and seeing colors and fine details. AMD leads to the irreversible loss of your “straight-ahead” vision and is divided into two types: dry macular degeneration and wet macular degeneration.
Dry macular degeneration is the most common form of AMD, affecting about 85-90% of patients1. Vision loss is typically gradual and may be identified by the development of yellow protein deposits, called drusen, under the retina6. Drusen occur when the macula tissues become thin and degenerate with age, but are also a fairly common occurrence in the natural aging process. Because of this, unless the drusen grow in size, they are not necessarily a predictor of AMD progression5.
In approximately 10% of dry AMD cases, macular degeneration progresses into the other form, wet macular degeneration. Wet macular degeneration results in 90% of the cases of legal blindness2. Wet macular degeneration happens when abnormal blood vessels begin to grow under the retina. Instead of providing nutrients and oxygen to the retina as blood vessels are meant to do, these new, more fragile veins leak blood and fluid and result in scarring, which can lead to severe central vision loss1. Damage from wet macular degeneration may progress more acutely and rapidly than dry macular degeneration.
Who is at risk?
The most prominent risk factor for AMD is, of course, age. As you age, your risk of getting AMD increases tenfold from age 50 to age 754.
Additional uncontrollable risk factors include a family history of AMD, race (Caucasians are more likely than other races to develop the disease) and being female (because they tend to live longer and therefore experience more of the aging process)1. Lifestyle behaviors, such as being overweight, having high blood pressure, smoking (which doubles your risk!), and not protecting your eyes against exposure to UV rays are also risk factors for AMD5.
What are the symptoms?
Early AMD has very few symptoms outside of the presence of drusen and may never progress to a later stage. Even the intermediate stage is still detected and defined almost exclusively by the size of drusen. Advanced AMD is identified by drusen size, loss of vision and the progression to wet AMD. Most people do not experience any noticeable vision impairment until their condition progresses to late stage AMD, when it is too late to save the vision that has been lost5. In addition, it is possible to develop more advanced AMD in only one eye, which makes symptoms even more difficult to detect.
If you notice any blurriness, dark areas or distortion in your central vision or any vision loss (all indicators of late stage AMD) you should make an appointment with an eye doctor5. It is important to note that because the progression of AMD and other age-related eye conditions such as dry eye, glaucoma or cataracts, are difficult to treat and sometimes impossible to reverse, making regular appointments with an eye doctor can literally save your sight.
How is AMD diagnosed?
Fig1. – Normal Amsler Grid.
Fig2. – AMD Amsler Grid.
Only a comprehensive eye exam can diagnose early signs of AMD1; it is, therefore, imperative that regular eye exams become a part of your health routine as you age. In addition to a visual acuity test and dilated eye exam (which allows a view into the back of your eye, including the retina and optical nerve), your doctor may also ask you to look at an Amsler grid (Fig1). If the lines in the grid appear wavy, blurry or disappear entirely (Fig2), it may be an indication of central vision loss due to AMD4.
Wet macular degeneration is usually diagnosed using a fluorescein angiography in which dye is used to visualize and detect any leaking blood vessels5.
How is AMD treated?
Treatments are different depending on the type and stage of AMD. In early stages, patients can adopt healthy habits such as exercise, eating healthy, or seeking out smoking cessation assistance. Taking these steps towards a healthy lifestyle may help slow the progression in the early stages of the disease5.
If you have intermediate or late stage AMD, your doctor may recommend a nutritional supplement based on the “AREDS” or “AREDS2” formula. AREDS stands for Age-Related Eye Disease Study, a clinical trial performed by the National Eye Institute that tested whether high doses of certain antioxidants and minerals had an effect on AMD. Researchers found that the daily intake of this formulation can delay or prevent the progression of AMD from the middle to advanced stage by about 25 percent7. The AREDS2 formulation contains vitamins and minerals that can be found in a wide variety of multi-vitamin options on the drugstore shelf. It’s important to discuss with your doctor which supplement is right for you. They may suggest a formula that contains additional ingredients for a complete eye health supplement instead of an AMD-focused formula or recommend a specific product.
The most severe form of AMD, wet macular degeneration, may also be treated with injections, laser surgery and photodynamic therapy, all aimed at stopping abnormal blood vessel growth. While these treatments are unlikely to cure or completely reverse the damage caused by AMD, they have been shown to slow AMD progression and prevent further vision loss1.
As we age, a certain amount of macular degeneration is bound to happen. It’s just part of the process. That does not mean, however, that everyone who ages loses their vision to AMD. By monitoring the development of drusen through regular, comprehensive eye exams and detecting any advancement early, you may be able to prevent, or at least slow down, significant progression and eyesight damage.
Citations:
- Haddrill, Marilyn ”What is Macular Degeneration?” All About Vision. 2016.
- ”Macular Degeneration: Frequently Asked Questions.” Bright Focus Foundation.. 2011.
- ”What is Macular Degeneration?” AMD.org. 2017.
- ”Age-Related Macular Degeneration: Facts and Figures.” BrightFocus Foundation. 2016.
- ”Facts About Age-Related Macular Degeneration.” National Eye Institute. 2015.
- Boyd, Kierstan”What Is Macular Degeneration?” American Academy of Ophthalmology. 2016.
- ”For the Public: What the AREDS Means for You.” National Eye Institute. 2013.
