Introduction
Macular degeneration is the most prevalent form of irreversible central vision loss in older adults. While certain rare forms of the disease can occur early in life, the majority of cases only begin to develop around the age of 50. For this reason, the condition is commonly referred to as age-related macular degeneration (ARMD). As the name implies, it is a degenerative condition affecting the macula, a razor-thin membrane located in the center of the retina that lines the majority of the rear interior of the eye. The retina houses millions of light-sensitive nerve cells called ganglion that absorb light focused on them by the cornea and the inner lens of the eye. This captured light is then transmitted through the optic nerve to the brain, where it is translated into the images we see.
Humans enjoy two primary types of vision: central and peripheral. Central vision is required for focused, straight-ahead tasks like reading, walking, using an electronic device, or speaking face-to-face with a loved one. It relies entirely on the macula, so damage or degeneration to the anatomy will eventually result in partial or total loss of central vision.
The second type of vision, peripheral vision, does not depend on the macula so it is unaffected by macular degeneration. Sometimes, people who experience central vision loss as a result of macular degeneration are able to adapt to the loss by more heavily relying on their peripheral vision. Creative use of peripheral vision, coupled with the brain’s ability to adapt to changing circumstance, allows these individuals to continue many of their normal daily activities without acute central vision abilities. In this scenario, an individual must focus on an object by turning their head at enough of an angle to allow peripheral light-sensitive cells to capture the light and formulate an image.
Wet vs. Dry Degeneration?
There are two forms of macular degeneration: dry and wet. Dry macular degeneration is by far the most common presentation of the disease, affecting roughly 90% of sufferers. It is driven by the relatively straightforward deterioration of the macula, a gradual process that can affect both or, for a period of time, only one eye. Sufferers often experience the sensation that one eye is no longer seeing as well as the other, and some objects viewed straight-on start to appear more and more distorted. This loss of clarity can also be accompanied by small, dark spots in the field of vision. While dry macular degeneration is the more prevalent form, it is thankfully also comparatively less serious. However, there are only a few effective medical treatments, chief among them learning to use the remaining peripheral vision to compensate for the growing loss of central vision.
While wet macular degeneration only affects about 10% of people who suffer from the disease, it accounts for over 90% of the most serious cases of vision loss. The condition is caused by the breakdown of tiny blood vessels in the retinal pigment epithelium (RPE), a microscopic layer of tissue that nourishes the retina from below. This breakdown causes small bleeds in this vital, sub-retinal layer of tissue and can lead to swelling, tears, and lesions in the retina itself. This deterioration, in turn, damages the light-sensitive nerve cells in the retina and the macula, leading to serious and rapid deterioration of central vision.
Wet macular degeneration can sometimes be treated with a specialized procedure during which a laser is used to cauterize leaking blood vessels to prevent them from causing further damage. This is done with the ultimate goal of slowing down the process of deterioration inside the eye. Another procedure, known as a fluorescein angiogram, is often performed to determine whether or not the retina is actively hemorrhaging; however, this procedure is merely diagnostic and offers no therapeutic benefits.
Diagnosis and Treatment
In addition to a fluorescein angiogram, the primary method of diagnosing age-related macular degeneration is called optical coherence tomography (OCT), in which a 3D photograph is taken of a patient’s eye, allowing the doctor to more closely examine the retina. Your physician can then see if swelling is present or if any of the layers of the retina are distorted, thereby confirming whether or not a patient’s reported vision problems are being caused by macular degeneration or something else. Finally, there is a simple at-home test for age-related macular degeneration called an Amsler Grid. The test is especially useful if a patient has already been diagnosed with macular degeneration in one eye, as there is a very high likelihood that the other eye will be affected sooner or later. In this case, early detection increases the chances of treatment being able to help preserve central vision capabilities in the newly-affected eye.
As stated above, the most effective treatment for dry age-related macular degeneration is to learn how to supplement declining central vision capabilities with peripheral vision, which is unaffected by macular degeneration. There are also certain pharmaceuticals, injections and laser-based procedures that can be done to help slow or reverse the progression of the disease. If you think you might be suffering from age-related macular degeneration, you should call Center for Sight at 850-476-9236 for immediate medical treatment, as timing is critical for many of the treatment options available to you. The sooner you act, the better your chances are of preserving some level of your central vision capability.