Age Related Macular Degeneration
What is Age-Related Macular Degeneration (AMD)?
Age-Related Macular Degeneration (AMD) is a condition that can affect the eyes of people over the age of 55 years, causing distortion and blurring of the central part of the vision.
It affects the macula, which is the central part of the retina, which is the structure of the eye that processes the visual information.
AMD is the leading cause of blindness in patients over the age of 55 in the Western World. Its incidence increases with age.
There are 2 types of macular degeneration: the “Dry” type and the “Wet” type.
The “Dry” type is by far the most common, accounting for 90% of patients with AMD. It causes a gradual reduction in vision, the end-stage being Geographic Atrophy, where central vision is significantly affected. There is currently no approved FDA treatment for this condition.
The “Wet” type is less common accounting for only 10% of AMD cases, however it causes the most damage to the central retina. In this form, new blood vessels grow under the retina, which can bleed or leak proteins and fluid causing significant damage and therefore reducing vision. The end-stage of this process is a large central macular scar – Disciform Scar.
What treatments are available for AMD?
There is evidence that vitamin and mineral supplements may reduce the progression of AMD in certain patients.
The US Food and Drug administration (FDA) has approved injections for the treatment of active “Wet” AMD. These include the new Anti-VEGF medications such as Macugen and Lucentis. Avastin is also used for this purpose as it has been shown to be safe and effective, although it does not currently have FDA approval. It is a popular choice for treating this condition as the cost is much lower than the other treatments currently approved by the FDA.
Results from a large study published in one of the most important ophthalmology journals, showed that taking supplements containing high levels of antioxidants and zinc, significantly reduced the risk of losing vision from age-related macular degeneration. People at high risk of losing vision from macular degeneration lowered their risk by about 25 percent when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene and zinc. The supplements benefitted patients with both the wet and dry forms of AMD. Supplements did not provide benefit for those with either early AMD or no AMD. Previous studies have suggested that people who have diets rich in green, leafy vegetables have a lower risk for developing AMD. Special consideration needs to be taken in patients who smoke, as the combination of beta-carotene and smoking increases the possibility of developing lung cancer.
Avastin is an antibody that binds to all forms of the natural human protein called Vascular Endothelial Growth Factor (VEGF). This VEGF stimulates the growth of and leakage from blood vessels in the eye, like the ones we see in Proliferative Diabetic Retinopathy, Vascular occlusions, Age-related macular Degeneration and Neovascular glaucoma. Avastin is the first commercially available angiogenesis inhibitor, that prevents the formation of abnormal blood vessels, therefore helping in the treatment of these conditions. Although currently not approved by FDA for use in the eye, numerous studies have demonstrated that it is a safe and effective treatment for specific eye disorders.
Side effects: minimal side-effects have been reported with the use of intravitreal Avastin. Complications that relate to all intravitreal injections include: Endophthalmitis (infection in the eye), inflammation, retinal detachment, cataract and glaucoma. However, we do not recommend you have an Avastin injection if you have had a heart attack or a stroke in the last 12 months.
Lucentis is an antibody derived from Avastin, specifically designed for use in the eye. It is a smaller molecule than Avastin and binds to VEGF-A. It is the only currently approved (by the FDA) angiogenesis inhibitor for the treatment of Wet Age-Related Macular Degeneration. Results from large phase III clinical trials ANCHOR and MARINA showed that 90% of Lucentis-treated patients stabilized vision and 40% improved vision by 3 lines on the chart. Monthly injections are required for 3 months, and further injections may be needed depending on response. Like Avastin, and because of the risk of thrombo-embolic events, we do not recommend a Lucentis injection if you have had a heart attack or a stroke in the last 12 months. No systemic side-effects have been reported with Lucentis.