Age-related macular degeneration (AMD) is a chronic disease of the macula, the part of the retina that controls how well we see in the centre of our vision, that we use for reading, seeing detail, and colour vision. AMD is the leading cause of blindness in people age 65 and over, and 1.75 million adults in North America suffer from its effects.
There are two types of macular degeneration: dry and wet.
Dry macular degeneration is the most common type of AMD. It occurs when yellow deposits called drusen build up in and around the macula and start to break it down. Over time, the drusen will start affecting central vision, causing blurred, speckled, or distorted vision. At any time, dry macular degeneration can become wet macular degeneration resulting in the potential for a more severe loss of central vision.
Wet macular degeneration accounts for only about 10% of those with AMD, but it is more severe and progresses more rapidly than dry macular degeneration. Abnormal blood vessels grow beneath the macula and may leak fluid or blood into the macular region. The fluid interferes with the retina’s function and vision starts to blur. Wet macular degeneration can lead to central vision loss in a very short period of time and almost always develops in people who have had dry macular degeneration.
Risk Factors for AMD
- Age – risk increases as you age, especially after age 50
- Family History of AMD
- Race – more common in caucasians
- Smoking – smoking cigarettes increases your risk
- Obesity – being severely overweight increases the chance the disease will progress to a more severe stage
- Unhealthy diet – a poor diet with little or no fruits or vegetables increases your risk
- Cardiovascular disease and elevated cholesterol may both increase your risk
Symptoms of Macular Degeneration
- distorted central vision
- a blurred or blind spot near the center of your vision
- visual distortions, such as straight lines looking wavy or crooked, objects appearing smaller than they really are
- decreased intensity or brightness of colours
- sudden change in vision
With any of these symptoms it is important to see us for an examination.
Treatment of Dry AMD
At this time, treatment can’t reverse dry macular degeneration, but this doesn’t mean you will eventually lose all your sight. Dry AMD usually progresses slowly and many people can live relatively normal lives. You should have annual eye examinations to ensure your condition is not worsening. Eating healthy and taking vitamins may reduce the progression of the disease to vision loss and in some cases vision has stabilized. Lutein and Zeanthanin and Meso-Zeanthanin are found in the macula and supplementation of these carotenoids can help. These are found naturally in foods like spinach, kale and collard but can also be supplemented. Large print books and a good light may assist reading, and glasses that provide a little more magnification may also be helpful.
Treatment of Wet AMD
Medications may help stop growth of new blood vessels by blocking the effects of growth signals the body sends to generate new blood vessels. These drugs are the first-line treatment for all stages of wet AMD. Current medications that are being used include: Avastin, Lucentis, Macugen and Eylea. These medications are injected by an ophthalmologist directly into the eye. Repeat injections may be required every 4 weeks to obtain the best result. In some cases, vision may be partially recovered as the blood vessels shrink and the fluid under the retina absorbs, allowing retinal cells to regain some function.
Be sure to make your yearly eye exam appointment so your doctor can check for signs of conditions like AMD and help preserve your vision.