AMD – Treatment
There is no treatment yet to halt the progression or recover any vision loss from dry AMD. However, the Age Related Eye Disease Study (AREDS) demonstrated that a specific formulation of anti-oxidant vitamins and minerals can reduce the risk of progression of dry AMD to more advanced stages and associated vision loss. The components of the AREDS formula are as follows:
- 500 mg Vitamin C
- 400 IU Vitamin E
- 15 mg Beta-carotene
- 80 mg Zinc oxide
- 2 mg Copper oxide
It is important to check with your medical doctor before starting this AREDS supplement. In general, Vitamin E supplementation should not exceed 400 IU, and smokers should not be on any Beta-carotene supplementation due to an increase risk of lung cancer. There are AREDS formula vitamins available that do not have Beta-carotene that are appropriate for smokers.
There are other potentially beneficial micronutrients such as lutein and zeaxanthin but these have yet to be proven to be helpful in treating dry AMD. Based on epidemiologic studies, certain lifestyle and nutritional changes may be beneficial. Based on what is known to date, the following recommendations may be made in hopes of improving the prognosis of dry AMD:
- Stop smoking. Smoking has been associated with vision loss and more advanced forms of AMD.
- Eat a diet rich in colorful vegetables and fruits. These food groups have been associated with lower rates of progression to advanced AMD and contain anti-oxidants (eg. Lutein) which may slow progression of disease.
- Control blood pressure. High blood pressure is associated with more advanced AMD.
- Consider eating food rich in Omega 3 fatty acids. Omega 3 fatty acids are found in cold water fish such as tuna and salmon and are believed to be associated with less advanced AMD.
- Be physically active. People with AMD who are physically active several times a week may reduce their risk for progression to advanced AMD and vision loss.
The prognosis for people with wet AMD is improving. There are more effective treatments now than was available just a few years ago but still no cures exist for AMD. Treatments include new drugs aimed at blocking growth factors, nondestructive laser-drug combinations, and traditional laser photocoagulation.
Anti-Vascular Endothelial Growth Factor (VEGF) Agents
The most recent treatment development for wet AMD was the FDA approval of Lucentis (ranibizumab) in 2006. This was the first treatment shown to improve vision in many people with wet AMD. Lucentis is administered in the office by an intraocular injection and typically dosed monthly for the first few treatments. The eye is prepped with antiseptic solutions and topical anesthetic drops. The injection is very well tolerated being relatively painless and only rarely associated with any complications. Treatment may need to continue indefinitely depending on the nature of the wet AMD and response to treatment, although the frequency and total number of injections may vary considerably among patients.
The risks of intraocular injections such as with Lucentis include hemorrhage, retinal tear, and infection, all of which are very rare. Anyone who receives an injection and subsequently has increased pain or loss of vision should contact their doctor immediately as these symptoms could indicate one of these rare complications.
Lucentis is a humanized antibody fragment that works by blocking an important growth factor of choroidal neovascularization called vascular endothelial growth factor (VEGF.) By blocking VEGF, both the growth and leakiness of the abnormal blood vessels is reduced. Studies with patients on a course of Lucentis showed that 70% of people on treatment will maintain or improve vision and 30% to 40% of people have relatively large degrees of visual improvement. However, there can still be vision loss despite ongoing Lucentis therapy.
Avastin (bevacizumab) is another drug used to treat wet AMD. Avastin is FDA-approved for use in people with certain types of cancer by intravenous infusion. Like Lucentis, Avastin is an antibody to VEGF. Retina specialists have been performing intraocular injections of Avastin to treat wet AMD for about as long as Lucentis. Although the use of Avastin injected into the eye is considered off-label, there are now studies that show Avastin to be as safe and effective to Lucentis.
Eylea (aflibercept) was recently approved by the FDA to treat wet AMD. Eylea is a fusion protein that acts like an antibody to bind VEGF. In clinical trials it had similar efficacy and safety to Lucentis. Time will tell (with additional studies) if there are any significant advantages of this agent to Lucentis (or Avastin.)
Macugen (pegaptanib) is growth inhibiting drug that blocks VEGF to some degree and can also slow the growth of choroidal neovascularization and to reduce leakage in the macula. Macugen was the first approved intraocular injection therapy for wet AMD, but is generally considered to be less effective than the other anti-VEGF agents and not used in practice much anymore.
Photodynamic Therapy (PDT)
Photodynamic therapy (PDT) with Visudyne (verteporfin) is another treatment for wet AMD. It utilizes an intravenous injection of a photosensitizing drug called Visudyne (verteporfin) and a non-thermal laser light to try and reduce leakage from certain types of choroidal neovascularization. It typically does not improve vision as when used alone, however, it is being explored as an adjunctive agent to anti-VEGF therapy such as Lucentis or Avastin and to intraocular steroid therapy.
PDT is a timed, office-based procedure. The Visudyne drug is infused into the vein over 10 minutes and then allowed to collect within the choroidal neovascularization over another 5 minutes. The choroidal neovascularization is then exposed to a low energy laser light for about 90 seconds to activate the drug only within abnormal blood vessels in the macula. This produces a chemical reaction within these abnormal blood vessels to reduce blood flow and leakage. The treatment is often repeated at 3 month intervals.
Visudyne clears itself completely from the body over several days. The skin and eyes must be protected from sunlight with clothing and special sunglasses for 2 days after the treatment. No driving is allowed while wearing the sunglasses. Sometimes PDT is combined with other treatments such as anti-VEGF agents or steroids to attack choroidal neovascularization using several different mechanisms of action.
Thermal laser photocoagulation may be used in certain, rare cases of choroidal neovascularization where the abnormal blood vessels are not beneath the center of the macula. Thermal laser treatment attempts to heat and destroy choroidal neovascularization but also damages overlying vision cells to some degree. Accordingly, this procedure is typically considered only when the abnormal blood vessels are far from the center of the macula. A major problem with thermal laser treatment is recurrent choroidal neovascularization which can develop in 50-60% of people.
Low vision aides may help improve the quality of life for people whose vision is impaired to the point that they cannot carry out important visual activities of daily living such as reading mail or writing checks. Low vision rehabilitation involves using specific magnifying optical devices and lighting aids to assist in performing specific vision functions. Although low vision aids are no cure for AMD, they may be helpful in performing essential visual tasks. Low vision centers can also be a good resource for non-optical aids such as books on tape, large print reading materials, and writing guides. An implantable miniature telescope was recently approved by the FDA and may be useful in certain patients with macula scars from AMD.