Photodynamic therapy (PDT) is a treatment for wet age-related macular degeneration (wet AMD). It involves the injection of a light-sensitive medicine into the bloodstream that then collects in the abnormal blood vessels under the macula. Laser light is then shone into the eye to activate the medicine so it creates blood clots that block the abnormal blood vessels. This procedure is not suitable for everyone and your doctor will decide if it might be an option for you, depending on the severity of your condition. While photodynamic therapy cannot restore lost vision or completely cure age-related macular degeneration, it can maintain the current vision and delay the natural worsening of the condition. Since no heat is generated with this laser, it is safe for the healthy tissue of the eye.
The procedure maintains current vision, stops the progression of disease, and seals off the abnormal blood vessels that are prone to bleeding (which affects vision). Some patients may feel their vision is better after the procedure and in others it simply keeps their vision from worsening.
-Photodynamic therapy can be used to selectively target the abnormal tissue with minimal effect on the surrounding intricate structures within the eye.
-Side effects such as blurriness and change may linger for a few days. This should however, resolve after a few days
Your pupil(s) will be dilated with eye drops before the procedure. You will be weighed to determine how much medication you should receive. You will be given verteporfin, a light-sensitive medication, intravenously over a period of approximately 10 minutes. This medication will travel through your bloodstream to the blood vessels of your macula. It will attach to the cells in the walls of the abnormal blood vessels. Laser light will then be shone into the eye to activate the medication and because no heat is used, healthy tissue will not be affected. (The doctor will have calculated the appropriate amount of medication and laser to be used to seal off the blood vessels). After the procedure your current vision should be maintained. In some patients with milder cases of age-related macular degeneration, vision may be restored to near normal. This procedure is considered fairly safe.
The ophthalmologist will carefully assess your eyes and carry out a special examination called a fluorescein angiogram that involves the injection of dye into the blood vessels of the eye to assess the location and severity of the condition. Prepare sunglasses and a long-sleeved shirt and pants to the procedure. The medication given causes light sensitivity throughout your body. Please let the doctor know about all medication that you are taking as some may need to be stopped before the procedure. Please also let the doctor know about any allergies you might have to medication. Patients undergoing laser therapy should not plan to drive themselves after the procedure as their pupil(s) will be dilated and that affects vision.
You will be asked to avoid all activities that may risk trauma to the eyes for at least one month after the procedure. After the procedure you will need to wear clothing that protects your skin from bright light. Wear sunglasses and a hat when going outside. The medication used can cause burning or redness of the skin in some patients due to its reaction to light. Once you are home from the hospital, plan to stay indoors for a day or two to avoid exposure to sunlight. Keep all follow-up appointments with your doctor to monitor the results of the treatment.
The risks of this procedure include:
-A new blind spot
-Back pain related to injection of the medicine
-Photosensitivity reactions like sunburn, if exposed to direct sunlight right after the procedure
-Reactions where you had the light-activated medicine injected
-Temporary loss of visual sharpness which rarely is severe Your risks may differ according to your age, other medical problems, and the specific anatomy of your AMD. Ask your eye doctor about your risks for the procedure. The effects of the therapy are often short-term. This is because the abnormal blood vessels may open up again.
Does this procedure hurt?
PDT does not hurt. A special contact lens will be placed on your eye to hold your lids apart and focus the "cold’ laser". Your eye may feel scratchy for a few hours after the PDT treatment, but there should be no pain.
What is the likelihood of success?
The success of the treatment will depend on the severity of the disease. The doctor will determine the most appropriate treatment for your condition and other treatments may need to be considered in conjunction with photodynamic therapy for the best results.
What if the procedure is not concerned?
If left untreated, age-related macular degeneration can lead to complete and permanent vision loss. Please discuss all options with your doctor.
What precautions are needed with PDT?
The light-activated dye (Verteporfin) can circulate through your body for up to 5 days after the PDT. Any intense light that you are exposed to during this 5-day period could result in severe sunburn. Care should be taken to avoid exposure of the skin and eyes to direct sunlight or bright indoor lights. Dark sunglasses and long-sleeved shirts should be worn when you need to go outside. “Bright lights” include but are not limited to: • Direct sunlight • Tanning salons • Halogen lighting in homes and offices • Lighting used in a dental office or surgical operating room