Age-related macular degeneration (AMD)
is the leading cause of blindness for those over 55.
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The eye doctors and Houston retinal specialists at The Eye Clinic of Texas offer diagnosis of age related macular degeneration (AMD) as well as treatment of AMD with Lucentis® Injections. Age Related Macular Degeneration (AMD) is a degenerative condition of the retina in which the central portion of the retina, called the macula, is damaged as a result of the hardening of the small arteries supplying oxygen and nutrients to the retinal tissue. The hardening and narrowing of these arteries deprives the macula of oxygen and nutrition. This results in a slow but progressive loss of function. The macula is responsible for providing central vision. Central vision is the sharpest or clearest area of your vision and is required for activities such as seeing fine detail of faces, reading and recognizing colors. The macula provides you with the precise vision required for driving a car and is responsible for central or “straight ahead” vision. The visual effects of macular degeneration can be relatively minimal with a mild “dimming” or “distortion” of your central vision, or very profound resulting in a complete loss of your central vision.
Macular Degeneration is an incurable eye disease and is the leading cause of legal blindness for those aged 55 and older in the United States, affecting more than 10 million Americans in some fashion. Your chances of developing Age Related Macular Degeneration (AMD) are directly related to your age. The older you are, the greater the chance that Macular Degeneration will affect you.
Types of Age Related Macular Degeneration
There are two main types of age related macular degeneration: Dry Macular Degeneration and Wet Macular Degeneration. It is important to understand the similarities and differences between these types of macular degeneration.
About Dry Macular Degeneration
Dry Macular Degeneration is the most common type of Age Related Macular Degeneration. Dry Macular Degeneration makes up approximately 85-90% of cases of Macular Degeneration. If you have Dry Macular Degeneration, during the examination of your Retina at SeeClearly Vision we will see small, yellow colored deposits between the retinal layers, which are called Drusen.
Dry Macular Degeneration results in a slow, gradual progressive “dimming” of your central vision. Many people 50 years of age or older begin to display some Drusen as they age. If you have Drusen, you may be asked to schedule eye examinations more frequently in order to monitor them as there is some possibility that Dry Macular Degeneration will progress to Wet Macular Degeneration over a period of time. Thus people with Dry Macular Degeneration, even without any noticeable change in vision, need to be followed closely as Wet Macular Degeneration has far more serious consequences for vision loss.
About Wet Macular Degeneration
Fortunately, Wet Macular Degeneration only accounts for about 10-15% of cases of Macular Degeneration, as it is likely to cause far more serious vision loss than Dry Macular Degeneration. Wet Macular Degeneration is characterized by an abnormal growth of new blood vessels under the retina. These new blood vessels are called neovascularization. Neovascularization is not made up of “normal” blood vessels in that they are unusually weak in their structure. In fact, they are quite fragile and are prone to be leaky and can easily break and bleed. If leakage occurs, the macula may actually begin to swell. If the new blood vessels break and bleeding occurs, it can result in scarring as it heals. Scarring of the Macula can cause severe loss of central vision, which may be irreversible.
Diagnosis & Symptoms of Macular Degeneration
As with many eye conditions and diseases, it is often possible to detect early signs of macular degeneration during your regular eye examination. Therefore, scheduling regular eye exams is an excellent way for the eye doctors at The Eye Clinic of Texas to make an early diagnosis of macular degeneration.
It is also important that you become familiar with the symptoms that may indicate the early presence of macular degeneration. If at any time you experience “distortion” or “twisting”, “shadowing” or “bending” of objects in your vision, you should schedule an appointment at The Eye Clinic of Texas immediately. Be sure to let the receptionist know that you are experiencing these symptoms.
If you are over the age of 40-45 and you have a family history of Macular Degeneration, we recommend that you have a thorough eye examination, including a dilated retinal evaluation, each year. Please be sure to tell our staff if you have a family history of macular degeneration. During your eye examination, eye drops will be put in your eyes to dilate your pupils in order to carefully examine the macula and retina using various types of instruments and sources of high magnification.
Additional tests that we may perform or order to further evaluate the Macula during your eye examination can include checking your color vision and an Amsler Grid Test. The Amsler Grid Test helps identify distortion of your central vision, and may be a subtle indication of swelling or fluid under the Macula.
The Amsler Grid Test
Although the Amsler Grid Test appears relatively simple, it is very useful in detecting small changes in your vision that can result from the accumulation of just a minimal amount of fluid under your macula. We may ask you to take an Amsler Grid home and use it to check for slight changes in your vision. If this is necessary, the doctor and staff will supply you with an Amsler Grid and detailed instructions on how to use it.
If, during your examination, we detect any signs of macular degeneration or believe that you may be at risk for Macular Degeneration, we may schedule you for additional testing with one of our retinal specialists.
In order to most precisely diagnose Macular Degeneration, it may be necessary to have detailed color photographs of your macula and retina taken. It may also be necessary for you to have a Fluorescein Angiogram (FA). To prepare you for a Fluorescein Angiogram, eye drops will be placed in your eyes to dilate your pupils. Then a fluorescent dye, called Sodium Fluorescein, will be injected into a vein in your arm. Do not be concerned, as this will not cause you to be uncomfortable. The dye will begin to circulate after about 10-15 seconds. At this time a series of photographs will be taken in rapid succession using a high-speed digital retinal camera as the dye passes throughout the retinal blood vessels. From these pictures it will be possible to see any fluid leakage or new blood vessel growth beneath the Retina. The FA will also show any changes or damage to the Macula and Retina and the extent of the changes. Most important, Intravenous Fluorescein Angiography gives our retina specialists a great deal of information regarding whether certain types of treatments such as Avastin® Injections or Lucentis® Injections might help stabilize your vision and prevent vision loss. Today, thanks to the advances in treating Wet Macular Degeneration, if caught early, it may be possible to avoid suffering significant vision loss.
Retinal Computer Imaging
At The Eye Clinic of Texas we use the most advanced computer imaging technology in order to make the earliest and most accurate diagnosis of macular degeneration. Our Retinal Computer Imaging system is called OCT or Ocular Coherence Tomography. The OCT uses a method called “optical coherence tomography” that is capable of creating digital images of the retina and Macula through the use of special beams of light in order to create a contour map of the retina and macula and detect microscopic changes in thickness or the accumulation of fluid beneath the Retina or Macula. This technique is similar to the CT Scans used to study organ systems and tissues throughout your body.
The goal of OCT Retinal Computer Imaging is to give us the ability to detect the slightest change in retinal or macula thickness, at the first possible moment, in order to diagnose macular degeneration at the earliest possible stage so that we can work to stop the progression of the disease and preserve your vision. We perform OCT Computer Imaging right in the comfort and convenience of our office at The Eye Clinic of Texas.
Treatment of Macular Degeneration
If macular degeneration is diagnosed early enough, we are very fortunate to have a number of possible treatment options that may help to slow or even halt the progression of vision loss. However, patients must understand that once the macula has been damaged, there is no treatment that currently can reverse that damage and the associated loss of vision. Early diagnosis and treatment to prevent or halt vision loss must be the approach that we take. Currently there are some treatment options available for certain types of macular degeneration.
Macular Laser Photocoagulation
The National Eye Institute (NEI) has sponsored a large scale multisite clinical trial in order to determine what particular macular conditions should be treated with lasers, what types of lasers should be used, which patients might get the best results and to try and establish the best ways to use lasers to treat macular degeneration. Our retina specialists routinely review results from studies such as The Macular Photocoagulation Study in the hope of finding a set of useful clinical guidelines for the Laser Treatment of Macular Degeneration. Unfortunately, the overall findings of the Macular Photocoagulation Study suggest that it is limited in its effectiveness.
Vascular Endothelial Growth Factor (VEGF) Inhibitor Injections
Avastin® and Lucentis® Injections
As a result of advanced cancer research in the area of “angiogenesis” or new blood vessel growth, considerable information has been gathered and applied to the treatment of Wet Macular Degeneration. Researchers discovered that a specific protein called “Vascular Endothelial Growth Factor” (VEGF) causes the growth of new blood vessels or “neovascularization” to occur in the eye. From this work, drugs that can be injected into the eye in order to slow or stop the growth of new blood vessels have been developed. Lucentis® has been developed and FDA approved with specific indications to treat Wet macular degeneration. Another drug, Avastin® has been FDA approved with an indication for the treatment of metastatic colorectal cancer and breast cancer. However, once a drug is approved by the FDA, physicians may use it “off-label” for other purposes if they are well-informed about the product, base its use on firm scientific method and sound medical evidence, and maintain records of its use and effects. Many Ophthalmologists now use Avastin® “off-label” to treat age related macular degeneration and other eye conditions that cause neovascularization, since research indicates that VEGF is one of the causes of the growth of the abnormal vessels that cause these conditions. Each of these drugs works by inhibiting Vascular Endothelial Growth Factor (VEGF) so that there is little or no stimulus to grow new blood vessels in the Retina.
Avastin® and Lucentis® Injections are intravitreal injections-that means an injection that is placed directly into the Vitreous of the eye. Generally they need to be repeated every four to six weeks. Clinical studies of these anti-VEGF Injections indicate that when given to patients who have evidence of new blood vessel formation monthly, over 90% of patients will maintain their vision.
Age Related Macular Degeneration & Diet
It is believed that nutrition may play a role in the likelihood of developing Macular Degeneration. Studies indicated that people who have a diet that is rich in fruits and vegetables-particularly green leafy vegetables-have a considerably lower incidence of Macular Degeneration. The Age Related Eye Disease Study (AREDS), which was sponsored by the National Eye Institute, showed that taking high levels of antioxidants and Zinc could reduce the risk of developing Age Related Macular Degeneration by about 25%. This is not a cure, but we need to consider this information as a possible way to help patients who are at risk for age related macular degeneration prevent vision loss.
NOTE: A VERY SPECIFIC FORMULATION WAS USED IN THIS STUDY
Before patients begin taking any course of vitamin or antioxidant supplements, you should fully discuss the risks and benefits with your eye doctor who in consultation with your family physician or Internist, will determine whether this is safe and effective for you to try.
If you or someone you know is concerned about macular degeneration or has a family history of macular degeneration (AMD) they should be sure to have regular eye exams at The Eye Clinic of Texas by calling 800-423-3737.