Photodynamic therapy for age-related macular degeneration: Overview
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.
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.
How well does photodynamic therapy for age-related macular degeneration work?
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.
What are the risks of photodynamic therapy for age-related macular degeneration?
A severe loss in visual clarity happens to some people who are treated with PDT. In some cases, vision partially recovers.
Other side effects that may occur with PDT include:
- Temporary visual disturbances (abnormal vision, decreased vision, defects in the visual field).
- Pain, swelling, bleeding, or inflammation at the site where the verteporfin medicine is injected. Some people also experience low back pain related to the injection of the medicine.
- Photosensitivity reactions (such as sunburn).
What can you expect as you recover from photodynamic therapy for age-related macular degeneration?
The verteporfin medicine used in PDT makes your skin and eyes more sensitive to light. After treatment, avoid direct sunlight for 2 to 5 days. And when you have to be outdoors, wear dark sunglasses to protect your eyes.
Your doctor will want you to come back for a follow-up exam in about a month.
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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