What is AMD?
Age-related macular degeneration is a leading cause of vision loss in older patients. It results in the loss of central vision (the macula) due to damage to the retina and the support structures of the retina. There are two forms of macular degeneration: "wet" and "dry". The most common type is the "dry" type of macular degeneration. This type of macular degeneration occurs as the result of many different factors including aging, genetics, and a variety of environmental factors. Most people with "dry" macular degeneration are relatively asymptomatic however a few patients can lose significant vision from the "dry" form. The most common examination finding associated with "dry" AMD is that of drusen. Drusen are yellowish deposits of cellular debris that accumulate beneath the retina. In addition to drusen, pigmentary changes and atrophy (or loss of tissue beneath the retina) can develop. A dilated examination of the retina can detect the presence of drusen, pigmentary changes, and atrophy. Importantly, a dilated retinal examination by a retina specialist (an ophthalmologist who further specializes in evaluating and treating the retina) can not only detect these changes but can also help assess the risk of progression to advanced AMD.
The "wet" (or exudative) form of macular degeneration is the result of abnormal blood vessels developing under the retina. These misplaced blood vessels can bleed or leak causing swelling under or within the retina. This can cause rapid loss of central vision. Patients may notice distorted or crooked lines or letters, missing images or faces, difficulty reading or driving, or other problems seeing. It is critical to recognize these changes as there are excellent treatments for "wet" AMD. Dr. Thompson prides himself on offering every option for the treatment of age-related macular degeneration to his patients.
MORE INFORMATION ON AGE-RELATED MACULAR DEGENERATION:
The macula is a region of the retina responsible for detailed central vision. For a variety of reasons, this area is predisposed to the development of macular degeneration. The retina is the light sensitive nerve tissue that lines the back of the eye and is responsible for your vision. The structures in the front of the eye (the cornea and lens) as well as glasses help to focus light onto the macula. The retina (and macula) is like the "film" in a camera whereas the cornea and lens are like the lens of the camera which serves to focus the image onto the "film".
The macular region is highlighted by the dotted line.
Dry (Non-Exudative) Macular Degeneration
The dry form of macular degeneration is characterized by the formation of drusen beneath the retina. Drusen are yellowish deposits consisting of cellular debris. Drusen can be classified based on their appearance, size, location and along with the presence of pigmentary changes can help to determine the risk for progressing to advanced AMD.
The clinical appearance of drusen in the macular region.
A cross-section of the retina showing the location of drusen (in yellow) beneath the retina and retinal pigment epithelium (RPE).
Wet (Exudative) Macular Degeneration
The wet form of macular degeneration occurs when blood vessels grow irregularly beneath the retina. These blood vessels often will "leak" (hence the term wet or exudative) or bleed resulting in significant vision loss. Patients will often notice distortion or blurred vision as these vessels develop. Bleeding can result in a dark spot (or scotoma) in the central vision. If recognized early in the process, these blood vessels can be treated often with some recovery of vision. In some cases the blood vessels can form a scar or the leakage can damage the retina resulting in a more limited chance for improvement in vision.
Hemorrhage from wet macular degeneration.
Cross-section of the retina affected by wet macular degeneration. Abnormal blood vessels (referred to as choroidal neovascularization) have developed beneath the retina.
A normal retina (and corresponding OCT) and that of a patient with wet age-related macular degeneration. The OCT (optical coherence tomography) is a scan that shows us the presence and activity of the abnormal blood vessels beneath the retina.
Amsler grid changes what a patient with wet macular degeneration "see: when testing their eyes.
Treatments for Wet Macular Degeneration
Premier Eye Care of Eastern Idaho is proud to offer every treatment option available for wet AMD. The newest treatments have been shown to dramatically reduce the leakage and bleeding from the abnormal blood vessels beneath the retina. These agents are not typical "drugs", rather they are in a new class of therapeutics called "biologics". "Biologics" are antibodies or fragments of antibodies created by a biologic process. These new therapies target the factor that causes abnormal blood vessel growth and leakage in the eye. This factor is called Vascular Endothelial Growth Factor (abbreviated VEGF) and is responsible for abnormal blood vessel growth not only in age-related macular degeneration but also diabetic retinopathy and retinal vascular occlusions. The newest therapies work by inhibiting (blocking) VEGF and are commonly referred to as "anti-VEGF" therapies.
Avastin (bevacizumab) was FDA-approved for the treatment of colorectal cancer in 2004. Avastin is a full-length antibody that binds to and inhibits VEGF. When used for cancer, Avastin is given every two weeks intravenously at very high doses compared to the dose used in the eye. In 2005 at the Bascom Palmer Eye Institute, Avastin was first injected into the eye for the treatment of wet macular degeneration. Doctors Rosenfeld, Moshfeghi, and Puliafito from Bascom Palmer later reported the great success they had using Avastin "off-label" for the treatment of wet macular degeneration. Just a few months after their initial report, Avastin became the most commonly used medication for the treatment of wet AMD. Because of the potential cost savings associated with using Avastin compared to other FDA-approved medications, the National Eye Institute sponsored the CATT Study comparing Avastin to Lucentis. The study demonstrated that Avastin was not inferior to Lucentis for wet AMD. There were no differences in safety between Avastin and Lucentis. Avastin is given as an injection into the vitreous (the gel inside the eye).
Lucentis (ranibizumab) was created by the same company as Avastin: Genentech. Lucentis was FDA-approved for the treatment of wet macular degeneration in 2006 based off the outstanding results of the phase 3 ANCHOR and MARINA studies. It became the first FDA-approved medication to improve vision in patients with wet AMD. Lucentis is an antibody fragment containing the site that "binds" the VEGF from Avastin. The fragment has undergone a process called affinity maturation that results in increased binding between the Lucentis and VEGF. Since approval in 2006, Lucentis has also gained FDA-approval for the treatment of macular edema secondary to branch and central retinal vein occlusions as well as diabetic macular edema. Lucentis is given as an injection into the vitreous.
Eylea (aflibercept) is the newest of the anti-VEGF therapies. Eylea was approved by the FDA for the treatment of wet macular degeneration in 2011. Eylea works in a similar manner to Lucentis and Avastin by binding VEGF. Instead of being an antibody or fragment of an antibody, it is a fusion protein that contains "decoy" VEGF receptors which bind and block VEGF. The VIEW 1 and 2 phase 3 clinical trials evaluated Eylea given every month for 3 months followed by every other month dosing versus Lucentis given monthly. The VIEW trials demonstrated that Eylea given less frequently (after 3 monthly doses) was equivalent to Lucentis given monthly. Eylea has also been approved for the treatment of macular edema secondary to branch and central retinal vein occlusions as well as diabetic macular edema. Eylea is given as an injection into the vitreous.
Premier Eye Care of Eastern Idaho proudly offers all available treatments to our patients including Avastin, Lucentis, and Eylea.
Other Treatment Options
Other Treatment Options
There are other treatment options for wet macular degeneration. These include photodynamic therapy (FDA-approved in 1999 for the treatment of some forms of wet AMD) and thermal laser treatments. Although these options are no longer considered "first-line" treatments for most patients with new onset wet AMD, they can still be utilized in certain patients to achieve optimal results. Dr. Thompson is skilled at utilizing these forms of therapy if they are needed.
Treatments for Dry Macular Degeneration
There are several lifestyle changes that have been linked to reducing your risk of macular degeneration:
1) Eat Your Vegetables.
Dark leafy green vegetables (specifically spinach and collard greens, and, by reasonable extension, kale, mustard, dandelion, and turnip greens) contain more lutein and zeaxanthin than other vegetables. Lutein and zeaxanthin are the chemicals studied in the AREDS2 (see below) which showed an additional risk reduction to the original AREDS formulation. Be sure to ask your doctor if a dietary change is right for you – especially if you are taking Coumadin as these vegetables have high levels of vitamin K.
2) Quit Smoking.
Many studies have established a relationship between smoking, even in small amounts, and macular degeneration..
3) Lose weight and exercise.
Both are associated with a lower risk of macular degeneration.
4) AREDS2 Eye Vitamins.
The only proven therapy to reduce the risk of progression from dry AMD to the wet form are AREDS2 vitamins. AREDS stands for Age-Related Eye Disease Study and the 2 is for the second study performed. The original AREDS was the largest randomized prospective study of macular degeneration ever undertaken. It concluded in 2001, was sponsored by the National Eye Institute (a part of the National Institute of Health or NIH), and it evaluated the risk of progression from dry AMD to wet over 5 and 10 years. The AREDS study discovered that a certain formulation of vitamins and antioxidants could reduce the risk of progression to advanced AMD by up to 25% for patients with intermediate and high-risk dry macular degeneration. In 2006, the AREDS2 was launched by the NEI to evaluate replacing beta carotene (linked to increased risk of lung cancer in smokers) with lutein/zeaxanthin and/or omega-3 fatty acids. An additional 18% risk reduction of developing advanced AMD over the five years of the study was seen in those patients taking lutein/zeaxanthin. There was no added benefit to omega-3 fatty acids. When taking eye vitamins, make sure they have the “AREDS2 formulation” in the labeling.