Photodynamic therapy is a treatment for the eyes. It uses a laser and a special medicine that works when exposed to a certain type of laser light. It is done to treat age-related macular degeneration (AMD). AMD is a condition that can lead to vision loss.

The retina is the layer of nerve cells that lines the back of your eye. It changes light into electrical signals. Your retina then sends these signals to your brain. The macula is the extra sensitive, central part of your retina. It is responsible for detailed, central vision. AMD damages your macula. The macula may become thinner as a result. Blood vessels may start growing under your retina. This can cause fluid to leak under your macula. This excess fluid can lead to vision loss.

Just before the procedure, a doctor who specializes in eyes (ophthalmologist) injects a medicine into a vein in your arm. This medicine is sensitive to light. It collects in the abnormal blood vessels under your macula. You are then given an anesthetic eye drop. Using a special contact lens, the doctor then shines a laser into your eye for less than 2 minutes. The light from the laser activates the medicine. The medicine then creates blood clots in the abnormal blood vessels under your retina. This seals off the vessels. This can help prevent more vision loss.

AMD is a common cause of major eyesight loss in older adults. In rare cases, it can lead to blindness. It only affects your macula. So you may still have your side (peripheral) vision if you have AMD. It may cause a sudden or slow loss of your central vision.

AMD comes in two main types: dry and wet. Only the wet type has abnormal blood vessel growth. Photodynamic therapy is recommended only for wet AMD.

Photodynamic therapy often doesn't restore vision that you have already lost. But it may slow down the damage to your central vision.

Photodynamic therapy is an option only for some people with wet AMD. It is used less often now that there are new medicines that are injected into the eye to reduce abnormal blood vessel growth. But your doctor may recommend it in addition to these newer medicines.

All procedures have risks. The risks of this procedure include:

• A new blind spot
• Back pain linked to injecting the medicine
• Sunburn, if your skin is exposed to direct sunlight right after the procedure
• Reactions in your skin where you had the light-activated medicine injected
• Short-term (temporary) or lifelong (permanent) loss of visual sharpness, which is rarely severe

Your risks may differ according to your age, other health problems, and the specific type of AMD. Ask your doctor about your risks for the procedure.

The effects of photodynamic therapy are often short-term. This is because the abnormal blood vessels may open up again. As a result, it often needs to be repeated every few months.

Ask your doctor what you need to do to get ready for photodynamic therapy. Ask if you need to stop taking any medicines before the procedure.

Your doctor may want to use special tools to shine a light in your eye and examine the back of your eye. You will need to have your eyes dilated for this eye exam. Your doctor might order other special tests to get even more information about your eye.

Before the procedure, eye drops will be used to dilate your pupil. It will stay dilated for several hours after the procedure.

It is most often done as an outpatient procedure in a doctor's office or eye clinic. This means you will go home the same day. During a typical procedure:

• You will be given an injection of the light-sensitive medicine into a vein.
• You will be awake during the procedure. You may be given medicine to help you relax.
• You will be given anesthetic eye drops to make sure you don't feel anything.
• You will have a special contact lens placed on your eye. This helps the laser focus on exactly the right spot in the back of your eye.
• Your doctor will shine the laser in the exact spot in your eye. This will activate the light-sensitive medicine. The medicine will form blood clots in the abnormal vessels under your macula. They seal off the abnormal blood vessels.
• Your eye may be covered for a short time.

Ask your doctor about what you should expect after your procedure. You should be able to go home the same day. Plan to have someone go home with you after the procedure.

For a few days after the procedure, your eyes and skin will be more sensitive to light. This is due to the light-sensitive medicine. During this time, you will need to stay indoors and stay out of direct sunlight. If you must go outside, use dark glasses and protective clothing and go back inside as soon as possible. Ask your doctor when it is safe for you to go outside again.

Your eye may be a little sore after the procedure. Talk with your doctor about taking over-the-counter pain medicine. Follow their orders about eye care and medicines.

You will need close follow-up care with your doctor. They will closely watch you for complications and keep managing your AMD. Tell your doctor right away if you have decreased vision or increased eye redness, swelling, or pain. Your vision may be blurry for a short while after the procedure. But this usually goes away.

Before you agree to the test or procedure, make sure you know:

• The name of the test or procedure
• The reason you are having the test or procedure
• What results to expect and what they mean
• The risks and benefits of the test or procedure
• What the possible side effects or complications are
• When and where you are to have the test or procedure
• Who will do the test or procedure and what that person's qualifications are
• What would happen if you did not have the test or procedure
• Any alternative tests or procedures to think about
• When and how you will get the results
• Who to call after the test or procedure if you have questions or problems
• How much you will have to pay for the test or procedure