More likely than not, you’ve heard of someone having macular degeneration. If you don’t, you may soon, as the National Eye Institute predicts the number of people having macular degeneration will increase 50% by 2020. But what is macular degeneration, besides hard to pronounce. First, lets have a quick anatomy lesson:
What is it?
The macula is a small area of the retina in the back of the eye. The retina’s job is to take light and convert it to a signal that the brain can interpret. The macula is in the center of the retina. This ¼ inch area controls 80% of central vision. Your ability to have detailed vision is made possible by the high concentration of cones in the macula. As an example, look at the corner of the screen and try to read this using your peripheral vision (side vision). Can’t do it? That’s because the macula is the structure that allows your eyes to see 20/20. Without it, vision would be closer to 20/400.
When the cones in the macula absorb light, the reaction creates waste products. The waste products are recycled to keep the vision produced by the macula crisp. Macular degeneration occurs when these waste products start to accumulate. The accumulation of these waste products are called drusen. As the number of drusen increases, the quality of vision goes down. Imagine watching a movie on an iMax screen. If someone took a needle and put a small hold in the screen, you probably wouldn’t notice it. If there were thousands of small holes clumped together, however, the picture would look distorted in that area of the screen. This is similar to how the build-up of drusen in the macula distorts vision.
There are two forms of macular degeneration: ‘dry’ and ‘wet’. The ‘dry’ form of macular degeneration is what is described above, the build up of drusen causes the image quality to go down. It is usually a slow, steady process. The degree of vision loss is often subtle. All forms of macular degeneration start as ‘dry’. The ‘wet’ form of the disease develops when the body tries to repair the ‘dry’ form of the disease. New blood vessels (neovascularization) are sent to repair the damaged areas of the retina. These new blood vessels are leaky, which causes the macula to split and stop working. Imagine trying to fix the iMax screen by climbing it without a ladder and filling the holes with a glue gun. Not only will it not work, but it will damage the screen even further in the process. The ‘wet’ form of macular degeneration causes a quick decrease in vision that can lead to blindness if left untreated.
Is there treatment?
To treat ‘wet’ macular degeneration, a retinal surgeon injects medication into the eye to prevent the new blood vessels from growing. While this doesn’t fix the macula, it prevents the problem from getting worse. There is no treatment for the ‘dry’ form of macular degeneration, other than to prevent it from coming the ‘wet’ form. The Age-Related Eye Disease Study (AREDS) found a combination of vitamins that have been shown to help prevent moderate to severe forms of ‘dry’ macular degeneration from turning into ‘wet’ macular degeneration. An update to the study in 2010 (AREDS2) re-evaluated the formulation and made it safer for patients that smoke.
Overall, the best way to treat macular degeneration is to prevent it from happening. There are 5 things that make you more likely to develop macular degeneration. Three of these things are out of our control: family history, demographics (more prevalent in Caucasian males), and age. We can control the other two factors: exposure to UV light and smoking. Quitting smoking and wearing polarized sun protection can reduce the risk of developing macular degeneration. There have been smaller studies that have looked at preventing macular degeneration through diet, supplementation, and exercise. While some of the results from these small studies have been promising, larger studies have shown they have little to no effect, making it difficult to recommend one regimen over another. The best recommendation I have heard to summarize these studies came from a retiring optometrist when I was in school: “your mother was right: finish your vegetables and stop sitting in front of the TV and get some exercise.” Overall, healthy people have healthy eyes. By keeping yourself healthy through diet and exercise, wearing sun protection, and staying away from smoking, you can reduce the likelihood of having your vision turn into an ‘iMax screen covered with holes’.