Age-Related Macular Degeneration (AMD)
Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye's macula. The macula is a small area in the retina — the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for central vision and seeing fine details clearly.
Many older people develop macular degeneration as part of the body's natural aging process. There are different kinds of macular problems, but the most common is age-related macular degeneration.
- Early AMD may be hardly noticeable and may only occur in one eye
- Words on a page may look blurred
- It may be difficult to recognize people's faces
- A dark or empty area may appear in the center of vision
- Straight lines may look distorted
Age-Related Macular Degeneration
Age-Related Macular Degeneration (AMD) occurs when a layer under the retina called the retinal pigment epithelium (RPE) is disrupted by deposits called drusen, or other age-related changes. These changes, if severe enough, may cause vision to deteriorate. When the macula breaks down, you lose your central vision, but it does not affect your peripheral (side) vision.
There are two types of Age-Related Macular Degeneration:
What is Atrophic or "Dry" Macular Degeneration?
Atrophic or "Dry" Macular Degeneration is caused by aging and thinning of macular tissues when drusen, deposits of tiny yellow or white pieces of fatty protein, are present and results in gradual vision loss. Dry AMD is the most common form of macular degeneration.
What is Exudative or "Wet" Macular Degeneration?
Exudative or "Wet" Macular Degeneration is caused by abnormal blood vessels forming underneath the retina. These vessels leak blood/fluid and blur central vision. With wet macular degeneration, vision loss may be rapid and severe.
Many people do not realize they have a macular problem until they notice blurred or distorted vision. Regular eye examinations by an eye care professional may help to detect problems before they are symptomatic.
The American Academy of Ophthalmology recommends that adults with no signs or risk factors for eye disease get a baseline eye disease screening at age 40 — the time when early signs of disease and changes in vision may start to occur. Based on the results of the initial screening, an ophthalmologist or optometrist may refer the patient to a specialist to treat a specific eye disease.
To examine for macular degeneration, Dr. Westrich or Dr. Metelitsina will dilate (enlarge) the pupils using eyedrops to examine the eyes with an ophthalmoscope, a device that allows him or her to see the retina and other areas at the back of the eye. If AMD is detected, he or she may recommend using an Amsler grid to check for wavy, blurry or dark areas in the vision.
What to expect at the first exam
Eye Care Specialists attempts to perform all necessary diagnostic tests and in-office treatment procedures on the day of an appointment in order to avoid the need for multiple visits. As a result, retinal subspecialty visits may take two to three hours. If a patient is diabetic, it may be necessary to bring a snack to the appointment.
At each retinal exam, the eyes will be dilated. Dilating drops enlarge the pupil so Dr. Westrich or Dr. Metelitsina can use special instruments to see the eye's entire lens, the retina itself, and the optic nerve.
It usually takes 20 to 30 minutes for dilating eyedrops to begin working. People with light eye color (such as blue, green or hazel) are more sensitive and dilate faster than people with dark eye color. Dilated eyes are are sensitive to light and near vision becomes fuzzy. Depending on the strength of dilating drops used, these effects can last for up to several hours. For these reasons, Eye Care Specialists recommends sunglasses and a driver for this exam.
Most retinal patients with macular degeneration will require a fluorescein angiogram. Dr. Westrich or Dr. Metelitsina usually perform this test at the office the same day as the exam.
This diagnostic test utilizes a camera, equipped with special filters that highlight the dye. The camera then takes rapid sequence photographs of the fluorescein as it circulates through the blood vessels of the retina. If blood vessels are abnormal, the dye may leak into the retina or stain the blood vessels. Many retinal conditions exhibit characteristic patterns of fluorescein staining. If there is damage to the lining underneath the retina, or the appearance of abnormal new blood vessels growing beneath the retina, their precise location will be revealed. The test enables Dr. Westrich or Dr. Metelitsina to confirm a diagnosis and determine the best treatment options. Post-treatment angiograms help to determine the effectiveness of the treatment.
Optical Coherence Topography (OCT)
OCT is a diagnostic test that scans the eye to provide high-resolution images of the retina. This allows Dr. Westrich or Dr. Metelitsina to determine the thickness of the macula and the presence of such things as edema, cystic changes, and subretinal fluid or hemorrhage.
Treating Dry AMD
Unfortunately, at this time there is no single proven treatment for the dry form of AMD. However, a large scientific study has shown that antioxidant vitamins and zinc may reduce the impact of AMD in some people by slowing its progression toward more advanced stages.
The Age-Related Eye Disease Study (AREDS) showed that among people at high risk for developing late-stage, or wet, AMD (such as those who have large amounts of drusen or who have significant vision loss in at least one eye), taking a dietary supplement of vitamin C, vitamin E, and beta carotene, along with zinc, lowered the risk of AMD progressing to advanced stages by about 25 percent (Click here for more information). The daily supplements also reduced the risk of vision loss for those at risk by about 19 percent. The supplements did not appear to provide a benefit for people with minimal AMD or people without evidence of AMD during the course of the study.
The AREDS nutrient supplementation shown to be beneficial includes:
- Vitamin C – 500 mg
- Vitamin E – 400 IU
- Beta carotene – 15 mg (25,000 IU)
- Zinc oxide – 80 mg
- Copper (as cupric oxide) – 2 mg (to prevent copper deficiency, which may be associated with taking high amounts of zinc)
NOTE: Please do not start a vitamin regimen without direction from an eye specialist.
However, vitamin supplements are not cures for AMD, nor can they restore vision already lost from AMD. It is not advised to start a supplement regimen until directed by Dr. Westrich or Dr. Metelitsina.
Treating Wet AMD
Thermal Laser Therapy
Thermal laser therapy is an outpatient procedure performed at the Eye Care Specialists office. This treatment is used when abnormal blood vessel growth is not under the center of macula. With thermal laser therapy, a high-energy, focused light beam treats a tiny area of retina by "burning" it; the laser beam destroys abnormal, underlying blood vessels, preventing further leakage, bleeding, and growth.
Following treatment, vision may be more blurred than before but may stabilize within a few weeks. A scar forms where treatment occurred, creating a permanent blind spot that might be noticeable in the field of vision. It is likely that 50 percent of wet AMD patients who have the thermal laser procedure will need retreatment within three to five years.
VEGF is the vascular endothelial growth factor chemical in your body that is critical in causing abnormal blood vessels to grow under the retina. Anti-VEGF Treatment is when an anti-VEGF drug, such as Lucentis, Eylea, or Avastin, is injected into the eye with a very fine needle. This reduces the growth of abnormal blood vessels, slows their leakage, and help slow vision loss. With Anti-VEGF treatments, Dr. Westrich or Dr. Metelitsina will clean around the eye to prevent infection and administer an anesthetic to the eye to prevent pain. Patients receive multiple anti-VEGF injections over the course of many months.
There is a very small risk of complications following anti-VEGF treatment, usually a result of the injection itself rather than the drug. In some cases, Dr. Westrich or Dr. Metelitsina may recommend combining anti-VEGF treatment with other therapies such as photodynamic laser therapy.
Photodynamic Therapy (PDT)
Photodynamic Therapy (PDT) is an outpatient procedure which uses a combination of a light-activated (photo-sensitive) drug and a special low-power (cool) laser. The photosensitive drug is injected into a vein in the arm, where it travels throughout the body; the drug attaches to molecules found in abnormal blood vessels. Laser light is targeted directly on the abnormal vessels, activating the drug; the drug causes damage specifically to those unwanted blood vessels. After PDT, abnormal blood vessels may reopen. Typically multiple treatments are required.