Age-Related Macular Degeneration

Macular degeneration may occur as part of the body’s natural aging process. The most common form is age-related macular degeneration (AMD). Diagnosing AMD in its earliest stages may help slow or manage its progression. In its earliest stages, a person may not be aware they have macular degeneration until they notice slight changes in their vision or until it is detected during an eye exam.

The macula is a small part of the retina. However, the macula affects our central vision – that’s how we’re able to drive, read, and recognize faces. Although a person's peripheral vision is left unaffected by AMD, the most important aspect of vision -- central vision -- is compromised. Macular degeneration by itself rarely causes total blindness and even those with advanced macular degeneration can continue to have some vision using their peripheral vision.

More than 2 million Americans age 50 and older have AMD. With Baby Boomers representing an increasingly larger percentage of the aging population, vision loss associated with macular degeneration is a growing health concern.


The Two Forms of AMD

Macular degeneration can be classified as either dry (non-neovascular) or wet (neovascular). Neovascular refers to the growth of new blood vessels in an area. In wet macular degeneration, the blood vessel growth may leak fluid or blood, negatively affecting central vision.

The dry form of AMD is more common – about 90% of all cases of macular degeneration are dry macular degeneration.

Dry macular degeneration. Dry macular degeneration is the early stage of the disease and vision loss is generally gradual. The tissues of the macula begin to thin with age and may stop working properly, resulting in some distortion or blurred central vision. If you notice even subtle changes in your vision, make an appointment with Dr. Johnson right away. Dry macular degeneration may progress to the more damaging form of AMD which is wet macular degeneration. Currently, there is no treatment or medication for dry macular degeneration. However, a handful of studies suggest some dry macular degeneration patients may benefit from vitamin therapy. One such study, conducted by the National Eye Institute (NEI), looked into the risk factors for developing macular degeneration and cataracts. The study, called the Age-Related Eye Disease Study (AREDS), showed high levels of antioxidants and zinc may significantly reduce the risk of advanced dry AMD and its associated vision loss. In May 2013, the NEI completed the AREDS 2, which tested several changes to the regimen because high levels of beta-carotene were associated with an increased risk of lung cancer in smokers. The AREDS 2 found lutein and zeaxanthin together appeared to be a safe alternative to beta-carotene.

Ask Dr. Johnson about an appropriate vitamin/antioxidant/nutrient regimen during your exam.

Wet macular degeneration. Wet macular degeneration is the more advanced and damaging stage of the disease. In about 10% of cases, dry macular degeneration progresses to wet macular degeneration. With wet macular degeneration, new blood vessels growing beneath the retina may leak blood or fluid. This leakage causes permanent damage to light-sensitive cells in the retina, causing blind spots or even a total loss of central vision in the affected eye. If abnormal blood vessel growth occurs in one eye, it may occur in the other eye. The sooner wet macular degeneration is diagnosed, the better the chances of preserving central vision. Regular exams to diagnose any eye disease and ongoing monitoring of your vision if you are diagnosed with AMD, are key to preserving as much vision as possible.


Risk Factors for Macular Degeneration

Oxidative stress is thought to play a major role in how macular degeneration occurs. Over the years, our bodies produce free radicals which may damage certain cells. Close to one-third of Caucasians have genetic changes that make them more susceptible to oxidative stress, which may lead to macular degeneration.

Another factor for macular degeneration is hereditary. Those with a close family member who has been diagnosed with macular degeneration are at a higher risk for developing the disease. An overactive immune system with its associated inflammation may be another risk factor for macular degeneration.

Obesity, abnormal (high) cholesterol levels, smoking, and/or high blood pressure are risk factors for developing macular degeneration. Both smoking and high blood pressure are linked to wet macular degeneration.

Lighter eye color, gender (female), overexposure to sunlight, and/or a high-fat diet are additional risk factors for developing macular degeneration.


How is Macular Degeneration Treated?

Currently, no outright cure for macular degeneration exists, but some treatments may delay its progression or even improve vision.

There are no FDA-approved treatments for dry macular degeneration, although nutritional intervention may be useful in preventing its progression to the more advanced wet form. For wet macular degeneration, there are several FDA-approved drugs aimed at stopping abnormal blood vessel growth and vision loss from the disease. In some cases, laser treatment of the retina may be recommended. Ask Dr. Johnson for details about the latest prevention and treatment options for macular degeneration.


Testing and Low Vision Devices

Although much progress has been made recently in macular degeneration treatment research, complete recovery of vision lost to AMD is unlikely. Dr. Johnson may ask you to check your vision regularly with an Amsler grid - a small chart of thin black lines arranged in a grid pattern. AMD causes the lines on the grid to appear wavy, distorted or broken. Viewing the Amsler grid separately with each eye helps you monitor your vision loss. If you have already suffered vision loss from AMD, low vision devices including high magnification reading glasses and hand-held telescopes may help you achieve better vision than regular prescription eyewear.




Schedule an Appointment to Discuss this Eye Condition  with Dr Johnson