By: S.C. Ali
Founder/Author
Age related macular degeneration (AMD) is one of the most common causes of vision loss in the elderly demographic. It is defined in basic terms as the degradation of the macula, which are multi-layered ganglia cells that are located approximately in the middle of the retina. For those who aren’t aware, the retina is one of the main portions in the eye. It is a, “light sensitive layer of tissue.” It has many important functions. However, for our purposes, one of the main functions of the retina is to absorb light, and then electrochemically excite the cells which then cause nerve impulses. These nerve impulses travel via the optic nerve through the brain. Thus, the retina can be viewed as somewhat of an important intermediary between what we see physically and our brain comprehending what we have seen.
When you go for a routine eye exam, your ophthalmologist/optometrist will look at the fundus (interior portion of your eye). It typically involves asking you to look straight ahead into an apparatus and stare at a point on an image. The macula shows up as a dark spot towards the middle (see picture 1 below).
Picture 1
As people age, this dark spot starts to fade and become less concentrated (see picture 2 below).
Picture 2
If a general ophthalmologist/optometrist sees this fading, they will make a note of it. Upon recommendation, the patient who has a degrading macula (hence the term “macular degeneration”) will be referred to a retina specialist for further treatment. A retina specialist is a board certified ophthalmologist who has completed additional fellowship training in retina care. In terms of vision, the patient’s vision becomes slightly blurred. Most importantly, if the patient is looking straight, the center part of the image is distorted. From the patient’s perspective, “straight lines appear wavy and parts of the grid may appear blank.” Although this does not lead to total blindness, it significantly impairs vision and thus quality of life.
Although age is the primary cause of macular degeneration, there are certain diseases that are potential risk factors, and associated with it. These include but are not limited to: high blood pressure (hypertension), obesity, Vitamin D deficiency, and smoking. There are a few other factors like high cholesterol and prolonged exposure to sunlight, but the data is more inconclusive for these two and thus further research is necessary. In addition, there are some genetic predispositions to developing macular degeneration. See this article for more details regarding the specific genetics involved. As a result of this polygenic factor, people who have a first degree relative with AMD have an increased risk and are advised to stay up to date with eye exams.
There are two main types of age-related macular degeneration: dry and wet. In dry macular degeneration, tiny extracellular material, called drusen, builds up “on the retina and beneath the macula”. It is typical for a small amount of drusen to build up over time. However, if too much drusen aggregates, it could be an early sign of AMD. Drusen is firm in nature hence the term, “dry.” According to Dr. Mogk, an international expert on age-related macular degeneration, dry AMD accounts for approximately 85% of all cases. This form of AMD tends to be a slow degradation. The other form of AMD, wet, is vascular in nature and accounts for about 15% of all AMD. This form is such more severe because according to Dr. Mogk, “abnormal blood vessels grow from the retina to the macula. This causes a bleeding or leakage of fluid, damaging the macula.” Because the wet version involves rupturing, the majority of severe vision loss cases in AMD are wet.
Unfortunately, there is no “cure” for age related macular degeneration. However, the goal of the ophthalmic team is to try and delay the deterioration of the macula as much as possible. There are a few options that look very promising. There is an FDA approved telescope implant that assists in gaining back the central vision that is lost with AMD. Again, this doesn’t regrow a macula by any means, but rather attempts to treat the effects caused by AMD. At the moment, the tiny implant is only for the most severe cases. The next type of treatment is pharmaceutical in nature, and tends to be used for wet macular degeneration. The two FDA approved treatments are ranibizumab/lucentis and bevacizumab/avastin. These medications are injected into the eye directly and work to inhibit growth of new blood vessels. Thus, it attempts to reverse the mechanism of wet AMD to a certain extent. These two medications are still undergoing clinical trials in order to determine the efficacy of each. Another type of treatment is laser photo-coagulation, where a laser is used to, “destroy or seal off new blood vessels to prevent leakage.” However, this can cause scar tissue. Thus, the laser isn’t as common as it once was.
In conclusion, with the large elderly population of baby boomers and the increasing life expectancy/rising senior population, being aware of AMD is of the utmost importance. Because there is no cure yet, it is difficult to treat AMD. However, there are some gold standards that can be implemented to slow the process. First of all, if you have a genetic predisposition to AMD, then you should see your local ophthalmologist for routine eye exams. The earlier it is detected, the quicker measures can be taken to reduce the deterioration. If diagnosed with AMD, there is a certain dietary regiment recommended by the National Eye Institute called the AREDS diet. It involves incorporating certain vitamins and minerals in your diet which includes but are not limited to: zinc, lutein, and omega-3 fatty acids. Please note that the literature shows that the AREDS diet doesn’t prevent AMD. Rather, it is recommended for if you have already been diagnosed with AMD. In addition, your retina specialist may implement a pharmaceutical regiment depending on if it is wet or dry AMD. In order to determine which treatment regimen is best for you or a loved one who has AMD, please consult your local ophthalmologist/retina specialist. For the future, we hope that researchers are able to devise a short term and long term cure for both wet and dry age-related macular degeneration.
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