What is photodynamic therapy?

Photodynamic Therapy

Photodynamic therapy (PDT)

Photodynamic therapy (PDT) uses medicine that is activated with light to kill cells. It is used to treat an eye disease called macular degeneration, some cancers, and skin problems such as acne.

For PDT, a medicine, called the photosensitizer, is put near the cells that need to be destroyed. The photosensitizer may be put on the skin, taken by mouth, or given in a vein. Then the photosensitizer is "turned on" (activated) with light. The light used is often from a laser or from light-emitting diodes (LEDs). The specific wavelength of light activates the medicine to make a kind of oxygen that kills nearby cells.

Photosensitizers will make the skin and eyes sensitive to light for about 6 weeks after treatment. So people who have PDT need to avoid direct sunlight and bright indoor lights.

Why is photodynamic therapy for age-related macular degeneration done?

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.

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