Despite the many advances in the care of eye diseases, age-related macular degeneration remains the leading cause of permanent vision loss among the elderly in the United States. Most likely, this disease will become even more common with the first wave of the “baby boomers” turning 60 this year. Macular degeneration is an aging disease of the macula, which is the central part of the retina. The macula is responsible for reading and for seeing fine details. Usually, macular degeneration affects only the macula, and not the rest of the eye, which means that in almost all cases, patients with macular degeneration will never become completely blind. They will usually maintain some peripheral vision, or vision “out of the corner of the eye.”

Macular degeneration comes in two forms; a more common non-exudative, or “dry” form, and a less common (but more severe) exudative, or “wet” form. Most people with macular degeneration have dry disease, although most people who lose significant amounts of vision have wet disease. A layer of cells underneath the macula is essential to maintain good vision. Dry macular degeneration is caused by deterioration or atrophy of these cells. There is also the formation of deposits called drusen, which usually do not cause vision loss by themselves but serve as a marker of the disease.

An abnormal new blood vessel growing underneath the macula always causes wet macular degeneration. These blood vessels are fragile, and leak fluid and blood, causing tiny retinal detachments, which affect central vision. In the past, there were no treatments available for dry macular degeneration. Some patients with wet disease were treated with laser, but this treatment was not helpful for many patients. However, there are now advancements in the diagnosis and treatment of all types of macular degeneration.

Laser Therapy
Traditional laser therapy (“hot” laser) for wet macular degeneration is becoming less common, because it is relatively ineffective and may cause significant side effects.

For several years, a newer treatment called photodynamic therapy (PDT) was very popular. Sometimes referred to as “cool” laser, PDT combines intravenous infusion of a medicatication (Visudyne), followed by treatment with a “photoactivator,” which is similar to a laser. PDT is occasionally combined with a medication (Kenalog), which is similar to cortisone. The triamcinolone is injected either adjacent to or directly into the eye, which appears to increase the effectiveness of PDT in some patients. Both “hot” laser and PDT can be performed in the ophthalmologist’s office. Both of these treatments are becoming less common, as newer medications gain in popularity.

Newer Medications
Both “hot” laser and PDT were attempts to destroy the abnormal blood vessels under the macula, however a newer strategy is to use medications aimed at blocking a protein called vascular endothelial growth factor (VEGF). VEGF is necessary for the growth of the abnormal blood vessels, which cause wet macular degeneration.

Pegaptanib (Macugen) was the first medication approved by the FDA to treat wet macular degeneration by interfering with VEGF. Macugen is not truly an antibody, but it works in a similar fashion by binding VEGF and preventing further growth of the abnormal blood vessel. Macugen is injected directly into the eye, and typically must be repeated at 6-week intervals for up to a year.

Bevacizumab (Avastin) is an anti-VEGF medication, which was approved by the FDA as an intravenous medication to treat complications of colon cancer. Although Avastin was not designed to be used in the eye, it is becoming a very popular treatment for wet macular degeneration. Injection of Avastin in to the eye is considered an “off-label” use of this medication.

Ranibizumab (Lucentis) is another anti-VEGF medication. It is similar to Avastin, although it was designed for use against wet macular degeneration. Lucentis received FDA approval on June 30, 2006 and may become the treatment of choice.

Surgical Therapy
Surgical therapy for wet macular degeneration is uncommon. However, surgery is occasionally useful for some patients with an unusually large hemorrhage under the macula. In addition, several experimental surgical procedures are being studied in various clinical trials.

Investigational Therapy
Several medications are in various stages of clinical testing including Anecortave acetate (Retaane), which is a cortisone-like medication that is injected adjacent to the eye. Retaane also is being studied as a treatment for wet macular degeneration, as well as a preventative treatment for patients with high-risk dry macular degeneration, still other experimental medications represent varying approaches to interference with VEGF.

Age-related macular degeneration remains the leading cause of permanent vision loss among the elderly in the United States. However, there are many new advances in the diagnosis and treatment of this condition. Your ophthalmologist or retinal specialist can determine if any of these treatments are right for you.

This article, authored by Stephen G. Schwartz, MD, appears in Radius magazine, Fall 2006. You can read more about Dr. Thompson and find additional health information at the Radius website www.radthemag.com.