Current Research & Treatment

Photodynamic Therapy

This technique consists of injecting a light-activated drug prior to the application of a special type of laser energy. The drug passes through and is retained by the abnormal vessels in the eye, absorbing the laser energy and closing the vessels. The goal is to destroy the unwanted new blood vessels without harming the surrounding tissues. The purpose of treatment is to stabilize vision; vision is seldom improved after treatment. Several treatment sessions are often needed to achieve closure of the new vessels.

In January 1999, the initial results were announced of a multi-center randomized clinical trial sponsored by QLT Phototherapeutics, Inc., involving 609 patients followed for one year. This study enrolled patients with wet AMD accompanied by new vessels under the center of the macula. After one year of follow-up, vision was stable or improved in 61.4% of treated eyes compared to 45.9% in eyes of patients given a placebo. Further analysis showed that a specific type of wet AMD (predominantly "classic" neovascularization) were most likely to benefit. In these individuals, vision was stabilized in approximately 67% of treated eyes compared to 39% of patients receiving the placebo. These results are statistically significant and indicate that certain patients with wet AMD for whom conventional laser therapy would not be beneficial can be helped with photodynamic therapy. . The two-year results showed that the treatment benefits persisted.

In April 2000, the FDA approved the drug (verteporfin or Visudyne) for photodynamic therapy. It is now available as a clinical treatment at the Macular Degeneration Center.

Most recently, Visudyne was reported to show some benefit for another form of wet AMD (occult neovascularization). Use of the drug for this form has yet to be approved by the FDA.
Miravant Medical Technologies is also evaluating photodynamic therapy and has completed enrolling patients in clinical trials at medical centers in a nationwide study (see Photodynamic Therapy Trial). Other drug companies are also developing products for photodynamic therapy, which are in the early testing stages.

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