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Age-Related Macular Degeneration

 

Anti-Vascular Endothelial Growth Factor (VEGF) Agents

In 2006, the FDA approved Lucentis (ranibizumab) for the treatment of wet AMD. 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 will continue to some degree on an indefinite basis in most patients 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 a serious infection.

Lucentis (ranibizumab) 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 the vast majority of patients maintained vision and that 30-40% experienced relatively large degrees of visual improvement. However, vision loss can still occur despite ongoing therapy with any anti-VEGF agent. For instance, a patient's underlying dry AMD (atrophy) is not treated by anti-VEGF medication.

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 is as effective as Lucentis in most cases.

Eylea (aflibercept) was approved in November 2011 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. In some cases it can be given less frequently.

Macugen (pegaptanib) is a 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 is not used in practice much anymore.

Photodynamic Therapy (PDT) with Visudyne (verteporfin) is another treatment for wet AMD. It utilizes an intravenous injection of a photosensitizing drug called verteporfin (Visudyne) 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 and to intraocular steroid therapy.

PDT is a timed, office-based procedure. The Visudyne drug is infused into a vein in the arm 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, during which the skin and eyes must be protected from sunlight with clothing and special sunglasses. 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.

Laser photocoagulation may be used in uncommon, specific 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.

Other Therapies

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 with a qualified low vision specialist can help identify special magnifying optical devices and lighting aids that can assist a patient in performing specific vision functions. 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. Computers and electronic readers (iPad, Kindle, etc) are often found to be very useful in the setting of vision loss from AMD.

In July 2010, an implantable miniature telescope was FDA approved for select patients with advanced end-stage macular degeneration in both eyes. This device has been shown to improve both vision and quality of life in select patients who have lost central vision in both eyes due to advanced AMD. It is implanted in one eye and magnifies images onto the healthy areas of the retina outside of the central area that has been damaged by AMD. This magnification aims to reducethe effect that the blind spot has on central vision. For additional information, please visit www.centrasight.com.


 

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