Macular Degeneration: Photodynamic Therapy

What is photodynamic therapy?

Photodynamic therapy (PDT) is a treatment used to try to seal leaking blood vessels caused by age-related macular degeneration (AMD). PDT involves injecting medicine in to your bloodstream, which is then activated by a laser light pointed at your eye. When activated, the medicine can close abnormal blood vessels in the eye and reduce your chance of losing vision. It does not usually improve vision.

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.

There are two forms of AMD:

• The dry form of AMD causes a slow breakdown of light-sensitive cells in the retina, and may not greatly affect the vision.
• The wet form happens when abnormal blood vessels grow under the retina. These vessels leak blood and fluid and cause scarring. Vision loss from this damage can happen quickly.

When is it used?

PDT may be used to treat some kinds of wet, age-related macular degeneration and similar conditions.

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.

Instead of this procedure, you might be able to have a different procedure, such as injections of medicine into the eye. You may choose not to have treatment. Ask your healthcare provider about your choices for treatment and the risks.

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)
• Plan for your care and a ride home after the procedure.
• Some medicines (like aspirin) may increase your risk of bleeding during or after the procedure. Ask your healthcare provider if you need to avoid taking any medicine or supplements before the procedure.
• You may or may not need to take your regular medicines the day of the procedure, depending on what they are and when you need to take them. Tell your healthcare provider about all medicines and supplements that you take.
• 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.
• Follow any other instructions your healthcare provider gives you.
• Ask any questions you have before the procedure. You should understand what your healthcare provider is going to do. You have the right to make decisions about your healthcare and to give permission for any tests or procedures.

What happens during the procedure?

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 will be very sensitive to sunlight, bright lights, and car headlights for several days. 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 to avoid severe sunburns. 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. Indoor light bulbs 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.

Ask your healthcare provider:

• how long it will take to recover
• what activities you should avoid
• how to take care of yourself at home and when you can return to your normal activities
• what symptoms or problems you should watch for and what to do if you have them

Make sure you know when you should come back for a checkup.

What are the risks of the procedure?

Your healthcare provider will explain the procedure and any risks. Some possible risks include:

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

Every procedure or treatment has risks. Ask your healthcare provider how these risks apply to you. Be sure to discuss any other questions or concerns that you may have.