Understanding Macular Degeneration (MD)
Many of our patients at the Eye Doctor’s Office are choosing the OCT Macular Degeneration Screening that we offer for the early detection and management of this visually debilitating and potentially blinding eye disease. With that it is important that we have a reasonably good understanding of this serious vision threatening disease.
- The goal of managing MD is to preserve visual function, including but not limited to visual acuity.
- To achieve this goal, early detection, monitoring, and treatment must be practiced.
- Eye doctors nationwide are missing MD in the course of an eye examination about 25% of the time.
- Currently, doctors are not carefully looking for the early subclinical and clinical signs and are too passive in treating when diagnosing macular degeneration. One reason is that in its very early stages MD does not affect the patient’s vision except for vision at night.
- Dry MD is often not diagnosed until the patient presents with drusen (to be defined in a moment) and visual acuity loss. By the time drusen is noted by the eye doctor and there is subjective vision loss the patient likely has had the disease for years and has lost some of the potential benefits of early detection.
- Because there is no cure for AMD, the goal is to halt or slow the disease progression.
- Earlier detection allows earlier treatment, which leads to better patient outcomes.
- With proper care, significant visual acuity loss may be prevented in many patients.
Earlier detection allows earlier treatment, which leads to better patient outcomes. With proper care, significant visual acuity loss may be prevented in many patients.
What Are Drusen (yellow deposits in or around the macular zone)
Drusen appearing as the yellow spots on the retina are the by-products of sick Retinal Pigment Epithelial cells (RPE)
- Retinal pigment epithelial cells are the most outer layer of the macula
- When the RPE cells become ill they deposit locally generated cholesterol beneath the RPE cell layer (In Bruch’s membrane) before Drusen are formed
- As MD progresses, cholesterol continues to accumulate, resulting in focal areas that are sufficiently thickened to be identified on the surface of the retina referred to as drusen.
- Thus, drusen caused by MD are the tip of an iceberg of the earliest lesions caused by MD.
- There is more cellular and vision dysfunction present than would be concluded simply on the appearance of drusen.
This cholesterol accumulation causes three primary insults to the macular and retina
- Oxidative stress, and
- Disruption of oxygen and nutrition supplied to the outer retina.
One of the early symptoms of macular Degeneration is poor night vision
Impaired dark adaptation is the first detectable consequence of AMD and can be used to identify patients with subclinical disease.
Dark Adaptation Testing
The next level of screening if the OCT Macular Degeneration Screening or other clinical signs are questionable is a new clinical tool called dark adaptation testing. It is highly sensitive and specific to detect MD and has a 90% accuracy. Although most, not all drusen are caused by MD and dark adaptation can help in those cases where the diagnosis of MD is questionable. Dark adaptation impairment can be present up to three years before MD shows up in a clinical eye exam at an eye doctor’s office.
As mentioned above the earlier the detection of MD the better the treatment outcome of slowing down this currently untreatable disease.
- Macular degeneration is present before drusen are visible through affecting dark adaptation, which is expressed by the patient as; ”My night vision is impaired”
- One functional aspect of the role of nutrients in MD that has been proven to be disrupted is vitamin A transport. Vitamin A is critical for rod-mediated dark adaptation. Please check with your primary care physician before you take additional supplements of Vitamin A
- Thus, impaired dark adaptation is the first detectable consequence of AMD and can be used to identify patients with subclinical macular degeneration disease.
Patients with impaired dark adaptation and small drusen have AMD
- Currently, there is no cure for MD.
- The management of MD has two primary goals,
- Preserving vision preventing progression to more advanced MD
- Effectively detecting and managing wet MD (Choroidal Neovascular Membranes)
- Achieving these goals will allow the patient to enjoy additional years of high-quality central vision, enhancing the odds of a better quality of life.
- Since people are living longer early diagnosis and consistent, aggressive management of the disease is required to minimize risk of vision loss.
- The importance of following your doctor’s orders to return for follow up care and monitoring cannot be overstated. The management of macular degeneration by your eye doctor is crucial to maintaining and prevention of permanent vision loss.
- Much of MD treatment is based on modifying risk factors, such as cessation of smoking, systemic disease management, proper diet (see below) including consumption of green leafy vegetables, weight control, sunglasses to minimize ultra violet (UVA and UVB) light exposure, exercise (3-4 times a week), multi-vitamins and other nutritionals like AREDS-2 OTC supplements and Omega fatty acids like fish oil.
- Smoking is the largest modifiable risk factor for the progression of both wet and dry macular degeneration. Current smokers carry a 5 to 4.8 times higher risk than non-smokers for late MD. Former smokers show less risk of development of late MD than current smokers, in a dose-dependent relationship. Encouraging smoking cessation is the best method to reduce risk of central vision loss. Exposure to secondary smoke is another risk factor for the developing of MD.
- There are, however, non-modifiable risk factors that still should be considered—namely Although we can’t do anything currently to alter a patient’s genetics, we need to realize that, moving forward.
- Genetic testing is currently available and being refined to identify and manage macular degeneration earlier. Knowing the outcome of treatments of relatives who have had MD will better prepare eye doctors to treat offspring of those relatives.
- Eye Injections (Anti-VEGF therapy) although often times beneficial for some patients to stop the inflammation and minimize the growth of unwanted blood vessels in the macular area are currently used in selected cases but may not be durable over the long term for some Our office works closely with retinal specialists at Texas Retina Associates of Dallas in the medical management of macular degeneration.
This diet includes high intake of fruits, legumes, vegetables, nuts, seeds, and other grains; olive oil as the main source of monounsaturated fat; dairy products, fish, poultry, and wine in moderate amounts; and limited intake of red and processed meats. Studies suggest that subjects who regularly consume a Mediterranean-like diet carry an overall lower risk of development of advanced AMD as compared to those who regularly consume a traditionally Western diet. A recommendation should be made that patients avoid traditionally “Western” dietary pitfalls (high glycemic index foods, high-fat dairy products, fried foods, and processed meats), and instead, follow healthier eating styles like the Mediterranean diet.