What is Macular Degeneration?
Age-related macular degeneration (also known as AMD or ARMD) is the leading cause of loss of visual acuity (sharpness) in adults over age 50. AMD is a deterioration of the retina and choroid.
- The retina is a thin layer of light-sensitive nerve tissue at the back of the eye (also known as the vitreous cavity).
- The macula is at the center of the retina. When we look at an object, the images are focused at the macula, and then converted to electrical impulses. The optic nerve carries these electrical impulses to the brain, and this allows us to see.
- The choroid is a layer of blood vessels and connective tissue between the retina and the white of the eye.
Types of Macular Degeneration
There are two types of macular degeneration. In later stages, both types involve loss of central vision, which affects the ability to read, drive, recognize faces, and do close-up work. Macular degeneration does not cause total blindness.
Dry AMD (also known as non-neovascular AMD)
- Drusen (small yellow lesions) form below the retina and may progress to early AMD.
- Sometimes progressive vision loss occurs, but not always.
- Areas of wasting (atrophy) may occur in the retina.
- Geographic atrophy (GA) indicates more widespread and serious atrophy in late stage dry AMD.
- Late stage dry AMD involves progressive central vision loss.
Wet AMD (also known as neovascular AMD)
- Abnormal blood vessels grow beneath the retina. They can bleed or leak, which causes swelling and damage to the macula.
- Common early symptoms are blind spots in the central vision, or distortion of straight lines.
- Symptoms can occur suddenly and cause noticeable vision damage.
Risk Factors for AMD
- Over age 60
- Family history of AMD
- Caucasian heritage
- Smoking
- High blood pressure
- Excessive sun exposure
- Dietary deficiencies
Can You Prevent Macular Degeneration?
Unfortunately, researchers have not found a way to prevent age-related macular degeneration. However, ophthalmologists believe that a healthy lifestyle can slow the development of the disease.
Doctors recommend reducing risk factors by:
- Quitting smoking
- Controlling blood pressure
- Wearing good quality sunglasses that protect against UV and HEV rays
- Eating a healthy diet that includes leafy green vegetables, fruit, and fish
Use of Vitamins
Researchers at the National Eye Institute conducted a large clinical trial a few years ago and found that daily use of vitamins A, B, and E slowed disease progression for certain dry age-related macular degeneration. Patients were less likely to develop wet macular degeneration after taking the vitamins.
There are several over the counter products that contain vitamins, as well as other ingredients that may be beneficial. However, some ingredients may actually be harmful to patients with a history of smoking. It is very important that an ophthalmologist evaluate your medical history and determine which formula is right for you.
So far there is no definitive research regarding the use of these vitamin products in patients who have normal vision and no symptoms of AMD.
How is AMD Diagnosed?
- A complete eye examination using drops to dilate the pupil.
- Amsler grid testing involves using a hand-held chart with a grid that can show visual distortion of straight lines.
- Optical coherence tomography (OCT), which is a painless and fast imaging test.
- Fluorescein angiography to identify abnormal blood vessels in wet AMD. This test is performed by injecting a vegetable dye into the vein of a patient’s arm while taking photographs of the retina.
Treatment of AMD
A qualified ophthalmologist should evaluate AMD test results to determine the best course of treatment for each patient. Many cases of AMD do not progress to serious vision loss, but it’s still important to schedule annual dilated exams to monitor your vision.
Additional methods of treating AMD include:
- Using an Amsler grid at home to monitor changes to your vision. If you notice any significant changes, contact your eye care specialist as soon as possible.
- Laser treatments can benefit some patients.
- Intra-vitreal injections – The injection of anti-VEGF (vascular endothelial growth factor) drugs into the vitreous cavity can be a highly effective treatment for advanced wet AMD. The drugs (ranibizumab, bevacizumab and aflibercept) stop the growth of new blood vessels in the eye. These injections are done as an office procedure. Patients require periodic monitoring of their disease to reevaluate for additional treatments with the anti-VEGF agents. Most patients require a series of injections.