The retina is the light sensitive tissue at the back of the eye that is connected to the optic nerve. Light hits the retina sending a signal through the optic nerve to the brain. Age Related Macular Degeneration (AMO} is a term that describes deterioration of the retinal cellular structure in the center of the retina, the macula. The macula is responsible for fine detail and reading vision. Damage to the macula results in loss of central vision and is usually gradual in the case of macular degeneration. Peripheral vision remains healthy in this condition. The central retina is dense with cone receptors. Peripheral vision does not have the retinal cones that permit fine detail but does allow the ability to navigate around and to see objects moving from the side and to distinguish large objects. It is recommended for patients to monitor changes that may occur in their vision and a good way to do that is by using an Amsler Grid twice weekly. With early diagnosis and proper treatment, the progression of AMO can often be delayed. The earlier AMO is detected, the better you chances are of keeping your vision.
There are two types of macular degeneration. The “dry” type and the “wet” type. The dry type generally causes a slow progressive loss of central visual acuity. It affects both eyes and may eventually cause a significant visual disability to read or to recognize faces and colors. There are currently no medications available to treat dry macular degeneration but certain lifestyle changes and vitamin therapies may be helpful to slow the progression of the disease. A clinical trial sponsored by the National Eye Institute studied the effect of nutritional therapy, along with higher quantities of certain vitamins and minerals and found that they may increase healthy pigments and support cell structure of the macula. No prescription is necessary. Dr. Srouji can discuss the use of antioxidant vitamins with you.
In the “wet” type there is a hemorrhage or fluid leakage in the retina area. Abnormal blood vessels develop underneath the retina to compensate for the loss of normal function but these new vessels are fragile and may leak causing permanent damage to the retinal tissue. This can occur in both eyes but usually happens in only one eye at a time.
In the past, laser was the only treatment. The problem with laser is that while it destroys the abnormal vessels it does destroy a portion of the retina so vision is lost. In the past few years, a new class of medicines have been developed in the form of an injection into the eye. A class of drugs known as anti-VEGF is the most recent and most commonly utilized treatment for the wet type of AMO. These medicines block a substance known as vascular endothelial growth factor or VEGF. By blocking or inhibiting this growth factor in the eye, the abnormal vessels will often stop leaking.
You do not have to receive treatment for your condition, although without treatment, wet macular degeneration and macular edema (swelling) may lead to further vision loss and sometimes very quickly.
At present, the FDA approved treatments for neovascular macular degeneration are: Photodynamic therapy with a drug called Visudyne and injections into the eye of the drugs Macugen, Lucentis, and Eylea. Although Visudyne and Macugen have been proven to slow down the rate of visual loss, most people do not get back better vision. Lucentis and Eylea have been compared and found to have equivalent efficacy and safety. In 2006, Ophthalmologists started using another anti-VEGF drug called Avastin to treat macular deneration and macular edema showing good results. The use of Avastin is “off label”. Avastin was not initially developed to treat eye conditions. Avastin is FDA approved for the treatment of colon cancer. Lucentis was designed by the same company that makes Avastin. Lucentis molecule is very similar to Avastin molecule. Clinical treals to date have shown that the two drugs have equal efficacy and no significant safety differences between the two. Eylea is relatively new and is FDA approved for the eye. It has been shown to produce similar results as Lucentis. The most commonly used medicines are Avastin and Eylea. The medication is injected into the eye at regular intervals every 4-8 weeks, often for several months until the leakage stops. In some patients the abnormal vessels will not come back but may return several months after the injections are stopped. As good as these treatments are, close follow up and often retreatment is necessary. The treatment plan is customized for each patient. Dr. Srouji will discuss with you the benefits and risks associated with these choices of treatment.
A dilated eye exam with an office procedure called fluorescein angiography is used to detect leaking and hemorrhaging vessels. In this diagnostic test, the damaged blood vessels associated with macular degeneration are imaged by injecting a fluorescent dye into the vein of the arm and tracing its progression through the retinal blood vessels. We also may perform an OCT (scan showing the topography of the retina) of the retina layers to determine the degree of fluid that has leaked underneath and into the retina.
While age related macular degeneration is most commonly associated with the elderly, there are hereditary and juvenile forms of maculopathy. In addition, a
“secondary type” of maculopathy may develop as a result of a vascular or inflammatory disease. This type usually affects only one eye and may not progress after the primary cause has been removed.
There are risk factors of AMD which include the following:
- Age – People over the age of 50 are at greater risk than any other age groups.
- Genetics – Recent studies have shown that there is a strong genetic component causing AMD.
- Race – Caucasians are much more likely to get AMD.
- Family History- Those with a family history of AMD are more likely to develop AMD.
- Smoking – Smoking and second hand smoke can drastically impact your chances of worsening AMD.
Here are some suggestions to help you see better:
Use a very bright light for reading as high as 300 watts may be necessary. Good quality high contrast print is the easiest to read. Low vision aids such as magnifiers and telescopic devices may be of value. When trying to read or watch TV, look slightly to one side rather than directly at it. Try up and down, right to left, until you find where you can see better.mes to improve the vision. Dr. Srouji will discuss with you the benefits and risks associated with these choices of treatment.