Photodynamic therapy is a special form of Laser treatment for Choroidal Neo Vascular Membrane (CNVM) due to various causes like – Age related Macular Degeneration (AMD), High Myopia, idiopathic and post inflammatory. As is evident by the name, this therapy is based on stimulation / activation of a photosensitive dye by exposure to a light (laser) of specific wavelength, which then closes the new vessels.

A special dye Verteporfin (Visudyne®) is used, which has a high affinity for these abnormal new vessels (CNVM). The dye is injected in the vein using a special pump. The dye gets selectively bound to these abnormal blood vessels. After injection, a special laser beam is focused on the affected area in the retina with the help of a contact lens. This laser, in itself does not damage the retina. The laser beam activates the dye and leads to closure of the abnormal blood vessels (CNVM). Since the dye is selectively bound to the abnormal blood vessels, this procedure helps us in selectively destroying the abnormal tissues with minimum or no damage to the normal tissue. This treatment modality for CNVM is most specific form of therapy available for selected cases of CNVM with minimal collateral damage to the normal tissues and maximum chance of maintaining vision.

This procedure itself takes only a few minutes and is usually painless and without any significant side effects. Some patients may complain of backache after the injection. The injected Verteporfin dye is a photosensitive dye. So the patient has to avoid sunlight or bright indoor light for a few days to avoid sunburns. You would be advised regarding the prevention and precautions during your pre-treatment counseling.

One must remember that usually multiple sittings of the treatment may be required. The aim of the treatment is to try and preserve and stabilize the vision, and not to improve vision. A large number of patients achieve stabilization of vision; some of the patients may even notice some improvement in vision also. Though being expensive, it is one of the best treatment modalities available today for selected cases with Neovascular membrane in AMD and high myopia. It is mandatory for the patients to maintain very regular follow up after this treatment, and monitor their vision regularly with the help of Amsler Grid.