Age-Related Macular Degeneration Information

Age-Related Macular Degeneration

What Is Age-Related Macular Degeneration

Age-Related Macular Degeneration, or AMD, occurs when the macula, an area of the retina that allows you to have detailed central vision, breaks down. It does not affect peripheral vision, which is the ability to see general shapes “out of the corner of your eye” even when you’re looking straight ahead. The macula is made up of millions of light-sensing cells that provide sharp, central vision. It is the most sensitive part of the retina, which is located at the back of the eye. The retina turns light into electrical signals and then sends these electrical signals through the optic nerve to the brain, where they are translated into the images we see. When the macula is damaged, the center of your field of view may appear blurry, distorted, or dark.

There are two main types of AMD:

Dry AMD (atrophic, non-neovascular) is the most common form. In Dry AMD, the tissues of the retina thin over time and small pieces of fatty protein develop under the retina, causing vision loss to occur gradually.
Wet AMD (exudative) only affects about 10% of patients with AMD. Typically, the condition develops in people who already have dry AMD. Wet AMD creates more damage than dry AMD and progresses more quickly as blood vessels grow under the retina and leak fluid or blood (exudate).

Age-Related Macular Degeneration (AMD) is the leading cause of permanent impairment of reading and fine or close-up vision among people aged 65 years and older, according to the Centers for Disease Control (CDC). The CDC estimates that 1.8 million Americans aged 40 years and older are affected by Age-Related Macular Degeneration (AMD). Another 7.3 million Americans who have large deposits in the retina called drusen, are at increased risk of developing AMD. By 2020, due to our aging populations, the number of Americans with AMD is predicted reach an estimated 2.95 million.

What Causes Age-Related Macular Degeneration

Risk Factors For Age-Related Macular Degeneration

Diagnosing Age-Related Macular Degeneration

If you or your doctor notice changes in your vision that suggest an eye disease or condition, you may be referred to an ophthalmologist (medical doctor specializing in the eye) for diagnosis. The early and intermediate stages of AMD usually start without symptoms. Only a comprehensive dilated eye exam can detect AMD. Below are the leading methods of diagnosis for eye diseases and conditions:

One of the first tests done may be a visual acuity test. Using an eye chart, your eye care professional can measure how well you see at distances. Other tests are more specific to the type of AMD suspected.

Dry AMD

Dilated eye exam.. During dilated eye exams, special eye drops are given to patients to dilate, or widen, the pupil. The widening of the pupil allows for more light to enter the eye, giving doctors a better view of the workings of inner eye components, like the retina. The drops take about twenty minutes to have their full effect. Once the pupil is fully dilated, the doctor can examine the eye with an ophthalmoscope, a specially designed optometric instrument to view the retina and other areas of the back of the eye. If he or she detects macular degeneration, an amsler grid (see below) can be conducted. The dilation caused by the drops can last for several hours following the exam, and typically results in temporarily blurred vision. If you are planning to drive to the doctor’s office, you may want to ask a family member or friend to accompany you in the event that your blurred vision lasts longer than expected and you are unable to drive home.
Amsler grid.If the doctor detects macular degeneration based on described symptoms or an ophthalmoscope examination, you will be asked to look at a chart called the Amsler Grid to check for AMD symptoms such as dark, wavy, or blurry areas in your range of vision. With AMD, typically only your central vision will be changed. Changes in your central vision may cause the lines in the grid to disappear or appear wavy, a sign of AMD.

Wet AMD

Fluorescein angiogram.An ophthalmologist, or eye doctor, performs this test by injecting a fluorescent dye into your arm. Pictures are taken as the dye passes through the blood vessels in your eye, which allows your doctor to see leaking blood vessels that occur in a severe, rapidly progressive type of AMD. In rare cases, complications to the injection may arise, from nausea to more severe allergic reactions.
Optical coherence tomography.OCT s a non-invasive imaging test using light waves to take pictures of your retina that may reveal abnormal blood vessels and macular damage contributing to wet AMD. Ultrasound, which uses sound waves to capture images of living tissues, is similar to how OCT test works, except that it uses light waves. An OCT can achieve very high-resolution images of any tissues that can be penetrated by light—such as the eyes. The light beam used for the OCT test is painless. Your eyes will first be dilated. Then you will be asked to place your head on a chin rest and hold still for several seconds while the images are obtained.
Fluorescein angiography. In this test, a fluorescein dye made of food coloring and fluoresces (naturally ‘glowing’ particles) is injected into a vein in your arm. Because of its fluorescent properties, the dye is able to be photographed as it travels to the eyes and through the retinal blood vessels, revealing any abnormalities that could be signs of wet AMD. Dye components put people who have allergies to shellfish and/or iodine at a higher risk of complication from this test, so be sure to let your doctor know of any food or medication allergies. Properly prescribed antihistamines may be able to prevent allergic reactions.

Symptoms of Age-Related Macular Degeneration

Prognosis

Living With Age-Related Macular Degeneration

Screening

Serious eye diseases and conditions often have no symptoms until irreversible damage to vision has been done. If you wear prescription glasses and/or contacts, you probably go to an optometrist for an annual check-up to make sure your prescription hasn’t changed and to order a new batch of contacts if you’re running out of them. Optometrists conduct vision tests to check for basic vision impairment, and can prescribe glasses and contact lenses. They can also spot early warning signs and give you a referral to an ophthalmologist, an eye doctor with a medical doctor degree, for a more thorough examination. If you do not wear contact lenses or glasses, chances are you miss out this periodic optometric screening. Many times, family doctors with conduct a visual acuity test, which is a series of letters decreasing in size on a chart that patients are asked to read to the best of their ability. This gives doctors the opportunity to do as the optometrists would.

The standard recommendation for all adults over the age of 40 is to have an eye exam at least every two years, and for adults over 65, to have an eye exam every year. According to the National Federation of the Blind, prompt detection and treatment can preserve your vision for a lifetime even if you do contract a serious eye condition or disorder. Schedule an eye exam with an optometrist. If he or she spots any problems that may be of concern, you will most likely be referred to an ophthalmologist, a medical doctor specializing in eyes, for further testing. Be sure to make an appointment with the ophthalmologist and follow recommendations regarding the frequency of follow-ups should any diseases or conditions be detected.

People with diabetes or at risk of developing gestational diabetes are recommended to get additional ophthalmic screening.

The American Academy of Ophthalmology recommends the eye screening schedule:
Type 1 Diabetes: Within five years of being diagnosed and yearly thereafter.
Type 2 Diabetes: At the time of diagnosis and yearly thereafter.
During pregnancy: During the first trimester and follow-ups if indicated.

Prevention

Medication And Treatment

Dry AMD According to Eyesmart.org, a service of the American Academy of Ophthalmology; there is no single treatment for the dry form of macular degeneration that works in all cases. However, the Age-Related Eye Disease Study 2 (AREDS2) showed that taking a dietary supplement of vitamin C, vitamin E, lutein and zeaxanthin, along with zinc, lowered the risk of dry AMD progressing to Wet AMD for some people. The supplements did not appear to benefit people with minimal macular degeneration.

Here is what was in the dietary supplement that was tested in the study:
•   Vitamin C – 500 mg
•   Vitamin E – 400 IU
•   Lutein – 10 mg
•   Zeaxanthin – 2 mg
•   Zinc oxide – 80 mg
•   Copper (as cupric oxide) – 2 mg (to prevent copper deficiency, which may be associated with taking high amounts of zinc)

Another large study showed that taking folic acid and vitamins B6 and B12 benefited women with AMD. Remember, however, that vitamin supplements don’t cure AMD or give you back any vision that has been lost.

Wet AMD The American Academy of Ophthalmology lists the following treatments that may reduce but not eliminate vision loss:
Anti-VEGF medication injection treatments. The injections contain drugs such as Avastin, Lucentis, and Eyelea that target a chemical called vascular endothelial growth factor (VEGF) in your body. VEGF causes abnormal blood vessels to grow under the retina.

In some cases, your ophthalmologist may recommend combining anti-VEGF treatment with other therapies:

Laser treatment. This is an outpatient procedure in the doctor’s office or at the hospital. A high-energy beam of light creates a small burn on the retina, destroying the abnormal blood vessels and preventing further leakage and growth.
Photodynamic therapy (PDT). This therapy uses a light-activated drug called a photosensitizer and a low-power, or cool, laser. The doctor injects the drug into a vein in your arm. It travels to the abnormal vessels behind the central macula and the low-power laser activates the drug, which causes damage to the unwanted blood vessels. Multiple treatments may be necessary.