Age-Related Macular Degeneration: Photodynamic Therapy

What is photodynamic therapy?

Photodynamic therapy (PDT) is a way to treat certain kinds of macular degeneration. The procedure involves using medicine called Visudyne, which is activated by laser light. When activated, the medicine can close abnormal blood vessels and reduce your chance of losing vision. It does not usually improve vision.

When is it used?

Photodynamic therapy may be used to treat some kinds of wet, age-related macular degeneration (AMD) and similar conditions. AMD is a disease that damages the macula in the eye. The macula is in the center of the retina. The retina is the lining at the back of the eye that senses light coming into the eye. The macula allows you to see fine details in the center of your field of vision. AMD can make it hard to read, drive, or recognize faces.

Wet AMD happens when new, fragile blood vessels grow under the macula. These vessels leak blood and fluid and cause scarring. Vision loss from this damage can happen quickly. PDT can be used to try to seal the blood vessels, which can decrease the chance of vision loss.

You will first have a special test called a fluorescein angiogram to check the type, size, and location of the abnormal blood vessels. Your provider will use the results of the angiogram to decide if PDT might work for you.

How do I prepare for the procedure?

Make sure you tell your provider:

• any other treatments you have had, such as radiation treatment
• any medical conditions you have, such as cirrhosis, porphyria, or diabetes
• any medicines you take (for example, tetracycline makes you more sensitive to light)

Because the medicine used in the procedure is activated by light, it is important to bring clothing that will protect your body from sunlight after the procedure. You will need sunglasses, long pants, a long-sleeve shirt, gloves, and hat.

Do not wear eye makeup on the day of the procedure.

What happens during the procedure?

First, your provider will review your fluorescein angiogram or possibly do a new one to measure the size and position of the abnormal blood vessels. You will be weighed and measured because the amount of medicine you will need is based on your body size. The medicine will be given through an IV for about 10 minutes. Some people have temporary back or chest pain while getting the medicine.

The provider will then place eyedrops in your eye to numb it. He or she will put a contact lens on your eye and ask that you place your head on a small platform in a slit-lamp instrument. Five minutes after the medicine was given, the provider will direct a laser beam to the area of abnormal blood vessels for just over a minute. This is painless, but you need to hold still. After the laser is turned off, the contact lens and IV are removed.

What happens after the procedure?

You may have blurry vision for a few minutes after the procedure.

This medicine makes your eyes and skin sensitive to light. You need to avoid exposure to sunlight and bright indoor light for 5 days. Wear sunglasses, long pants, a long-sleeve shirt, a hat, and gloves when you are outside. Ask your healthcare provider about the best type of sunglasses to wear during this time. Avoid bright indoor light and sunlight coming in from windows. Don't worry about light from light bulbs. They are too weak to activate the drug. Operating room lights can activate the drug, so do not have surgery during this time. Your provider may give you a wristband to wear that describes the treatment you had. Wear the wristband for 5 days after the procedure. The wristband tells healthcare providers that you have taken this medicine if you need emergency care or surgery.

Usually you will have a follow-up appointment for an exam and another angiogram 6 to 12 weeks after the procedure. You may need 5 or 6 PDT treatments over the course of a year.

What are the benefits of this procedure?

For some forms of age-related macular degeneration, PDT has been shown to reduce the risk of losing more vision over time.

What are the risks of the procedure?

This medicine causes you to be very sensitive to sunlight, bright lights, and car headlights for several days. Protect yourself from sunlight and bright indoor light for 5 days after a treatment to avoid severe sunburns.

You will probably have some changes with your vision that come and go after treatment. Rarely, severe vision loss happens soon after a photodynamic treatment.

When should I call my eye care provider?

Call your eye care provider's office if you have:

• hives
• trouble breathing
• sudden loss of vision
• a severe sunburn
• other unexpected symptoms.

These problems are very rare.