Photodynamic Therapy (PDT)

Photodynamic therapy or PDT is a treatment that uses a special drug, a photosensitizing agent, along with light to damage and close abnormal blood vessels. It can be used in conjunction with intravitreal injections (combination therapy) or by itself to damage and close the abnormal blood vessels that form under the retina in patients with the wet form of macular degeneration. The PDT drug only works after it has been activated or “turned on” by certain kinds of light.

If you and your doctor decide this course of treatment is right for your eye condition, you will usually be scheduled for another visit and be informed to wear clothing that will protect your skin and eyes form direct sunlight (hat, long sleeve shirt, sunglasses, etc.) for 5 days following therapy.

On the day of your PDT visit you will be screened and weighed to determine the proper amount of the vereporfin (Visudyne) drug that will be for you. You will then have a slow 10 minute infusion of the drug through your arm vein. Fifteen minutes after the infusion begins you will be seated in front of the laser and the doctor will place a special contact lens on your eye. The laser session will begin by the doctor directing the laser through the contact lens onto the affected area of the retina and applying the laser for about one and a half minutes. The light causes the activation of the drug within the abnormal blood vessels, which damages and closes the abnormal blood vessels stopping the leakage. This is a cold laser therapy, there is no heat involved, so it will not burn the retina or surrounding tissue.

Multiple courses of the therapy may be necessary if the abnormal blood vessels do not fully close off and leakage still occurs.