EARLY MACULAR DEGENERATION
Many people with macular degeneration experience minimal vision loss during the early stages of the disease. For most people, macular degeneration does not become vision impairing. During this stage, the transport of wastes and nutrients by the RPE has slowed down. As a result, waste builds up under the retina and forms yellowish deposits known as drusen.
An ophthalmologist examining a patient at this stage may see drusen, although no symptoms may be present or develop later. If the doctor sees drusen, the patient will be monitored. In most cases, the disease will not progress to vision loss, although some patients do experience vision loss with drusen. Many patients over 60 have some drusen.
There are two types of AMD:
Macular degeneration may progress into dry (atrophic) macular degeneration or wet (exudative) macular degeneration.
– Dry AMD is the initial stage of the disease. This condition rarely leads to severe vision problems or blindness. Visual changes often lead to the loss of function, which may cause a blind spot or scotoma in the central vision.
– Wet AMD arises from Dry AMD and is characterized by the new abnormal blood vessels that grow under the retinal pigment epithelium, under the retina, or even within the retina. If untreated, Wet AMD may cause blind spots and, in severe cases, lead to vision loss.
DRY AGE-RELATED MACULAR DEGENERATION
Dry macular degeneration generally progresses slowly as drusen accumulate in the retina. This condition rarely leads to severe vision problems or blindness. While portions of the RPE continue to slowly transport wastes and nutrients, photoreceptors accrue damage over time. The number and size of drusen increase in the macula.
Visual changes often correlate with the loss of function of the corresponding areas of the retina. Sometimes large regions of cells are lost. This is known as geographic atrophy. Geographic atrophy may cause a blind spot or scotoma in the central vision.
If you have dry macular degeneration, you should tell your ophthalmologist about any changes in your vision immediately. Regular exams along with self-monitoring using the Amsler Grid or other devices are necessary for preserving your vision. Patients with dry macular degeneration can develop wet macular degeneration, for which effective treatment is available if instituted in a timely manner.
Aside from managing your risk factors and vitamin therapy, there is currently no other prevention or treatment for dry macular degeneration. Luckily, most people with dry macular degeneration do not progress to more advanced geographic atrophy or the wet form. Preventing dry macular degeneration or halting its progression are areas of intense research. VRMNY is actively participating in promising trials dedicated to this endeavor.
WET AGE-RELATED MACULAR DEGENERATION
People with large drusen, many drusen that run together, or focal pigmentation are more likely to develop wet macular degeneration. With this form of the disease, new abnormal blood vessels grow under the retinal pigment epithelium, under the retina, or even within the retina. These new blood vessels originate in the context of choroidal neovascularization (CNV).
It is believed that these new blood vessels form in response to impaired retinal nutrient supply and the slowed transport of wastes. New blood vessels often leak blood or fluid under or into the retina. As this happens, the surface of the retina becomes uneven, thus objects in that part of the vision field may appear distorted, wavy, or blurry. The new blood vessels may break through some of the retinal layers. If parts of the retina become damaged by these blood vessels, it may cause blind spots.
In most cases, the first sign of fluid under the retina is the appearance of distorted straight lines. Regular testing with an Amsler Grid can be helpful in detecting problems early. If detected early, new blood vessels can be treated before they cause too much damage. Ultimately, untreated neovascularization and leakage can cause the overlying photoreceptors to die and macular scarring. The final stage of macular degeneration is scarring, which in most cases leads to vision loss.
Macular degeneration only affects central vision, and although it is the leading cause of legal blindness, it rarely causes total blindness. In other words, even patients with very advanced stages of the disease are able to navigate their homes and neighborhoods and will not have to depend on guide dogs or other aids that are commonly associated with total blindness.
