Photodynamic Therapy (PDT): New Therapy for AMD

Since FDA approval of Visudyne (Verteporfin for injection, Novartis), Photodynmic Therapy (PDT) has become the mainstay of treatment for patients with subfoveal or submacular choroidal neovascularization.   Stated another way, patients with the wet form of the disease that develop abnormal blood vessels underneath the macula respond well to this new treatment. PDT is a treatment that usually needs to be repeated. Most patients may require 3-4 treatments over the first year and about 2 treatments over the second year. Significant preservation of vision can be acheived when adhering to this protocol.   Many patients may also improve vision after initial treatment with subsequent treatments able to sustain this improvement.

PDT involves injection of a medicine (Verteporphin) which will accumulate in the abnormal vascular complex. This infusion occurs over a 10 minute period. The amount of drug administered is based upon the body mass index (BMI) which is a derivation based upon the individual's height and weight. A “cold” or nonthermal laser (689 nm) is applied for 83 seconds to convert the accumulated Verteporphin to a form which is toxic to the abnormal blood vessels. In this way only the abnormal tissue is affected and surround normal tissue remains unaffected! This is in contrast to initial treatments using thermal lasers.