Photodynamic therapy

Photodynamic therapy (PDT) is a treatment for wet age-related macular degeneration (wet AMD). It is not used to treat dry AMD.

Photodynamic therapy may be recommended if you can't have injections of medicines to treat your AMD or if these injections don't work.

In photodynamic therapy, a light-sensitive medicine called verteporfin (Visudyne) is injected into the bloodstream. The medicine collects in the abnormal blood vessels under the macula. Laser light is then shone into the eye, which activates the medicine and causes it to create blood clots that block the abnormal blood vessels. By sealing the leaky blood vessels, photodynamic therapy slows down central vision loss.

Photodynamic therapy takes about 20 minutes and may be done in a doctor's office or eye clinic.

The main treatment for wet AMD is injections of anti-VEGF medicines into the eye. Photodynamic therapy is not usually recommended. But when anti-VEGF injections can't be used or don't work, photodynamic therapy is one option that may be recommended.

By limiting the growth of abnormal blood vessels under the macula, photodynamic therapy may help prevent the progression of wet AMD. It does not restore vision to eyes that have already been damaged. But it may help prevent further damage to the retina and further vision loss.

PDT can lower the risk of severe vision loss by reducing the growth of and leakage from abnormal blood vessels under the retina. How well the treatment works depends on where and how the abnormal blood vessels are growing beneath the retina. For some types of wet AMD, the treatment has no detectable benefit.

The effect of PDT in slowing the progress of AMD is often temporary, and the abnormal blood vessels begin leaking again after about 3 months. Most people need multiple treatments to get the full benefits of the therapy.