What is macular degeneration?
Age-related macular degeneration (AMD) is a condition that causes disruption to a small area of the retina called the macula. The macula is about 5 millimeters in size and is responsible for our central vision, allowing us to see fine detail. As the macula begins to degenerate in AMD, patients experience blurred or distorted central vision. AMD is the leading cause of blindness in people over 55 and impacts more than 10 million people in the United States.
A properly functioning retina contains many layers that all work together to process light into clear vision. Beneath these retinal layers is another thin layer responsible for supplying nutrients and removing wastes from the retina, called the retinal pigment epithelium (RPE). In AMD, the RPE loses the ability to rid the retina of waste products, resulting in a buildup of deposits called drusen. It is important to know that, in most cases, patients with a few small drusen never progress to severe AMD and central vision loss. In patients with progressive AMD, drusen increase in size and number. This results in a lack of nutrients supplied to the retina.
Dry vs. Wet Macular Degeneration
As the nutrient supply to the retina weakens with AMD, blood vessels sprouted from the surrounding layers of the eye infiltrate the diseased macula. This is the eye’s attempt to provide nutrients to this undernourished area of retina. Unfortunately, these newly developed blood vessels are very fragile and often leak blood into the macula. If these new blood vessels grow and leak, it is called wet AMD (or exudative AMD). Wet AMD occurs in only 10% of all AMD cases. Vision loss caused by wet AMD often occurs much faster than dry AMD. Most cases of AMD are dry (or non-exudative AMD), meaning these blood vessels never develop. It is important for the doctor to make this distinction because the treatment and management for dry versus wet AMD is much different.
What are the risk factors for AMD?
- Smoking
- Having a family history
- Obesity
- A diet high in saturated fat
- Age over 50
- Caucasian ethnicity
- Excessive exposure to UV light
What are the symptoms of AMD?
- blurred central vision
- distorted or wavy vision
- difficulty reading
- change in color vision
Are there treatments or preventative measures?
Unfortunately, there are no proven curative treatments available for patients with AMD. However, there are measures that can be taken to help combat and slow the progression of the disease. A specific formulation of antioxidants and vitamins, called the AREDS 2 formulation, has proven effective in helping patients with mild AMD. Studies found that taking these vitamins lowers the chances of mild AMD worsening to more advanced forms. For smokers, cessation is another important step to lower the risk of progression. In addition, sunglasses should be worn outside to protect the retina from excessive exposure to ultraviolet light.
For wet AMD, development and growth of new blood vessels can be managed with laser treatments, photodynamic therapy, and/or anti-VEGF injections. These treatments are very effective at halting further progression and sometimes result in improved vision.
Is there anything that can help me see better?
While there are currently no treatments to permanently reverse the vision loss caused by AMD, we do have access to rehabilitation services and low-vision devices that help optimize patients’ functional vision. These specialty devices include hand-held and video magnifiers, computer programs, large print books, and other ophthalmic devices.
