|Visudyne was approved by the Food and Drug Administration (FDA) in April of 2000 as the first drug treatment for only a certain form of wet age-related macular degeneration (AMD).|
Treatment for Wet Macular Degeneration
The type of macular degeneration that visudyne medication treats is called predominantly classic wet AMD. or predominantly classic subfoveal choroidal neovascularization.
At this time this macular degeneration medication is not indicated for the treatment of predominantly occult subfoveal choroidal neovascularization.
The trade name for this drug is verteporfin. It is used in photodynamic therapy (PDT). Photodynamic therapy for macular degeneration is based on a technology that uses light-activated drugs to treat a wide range of medical conditions. Some diseases in which there are fast-growing tissues can potentially be treated with this technology.
This macular degeneration therapy can lower the risk of severe vision loss by reducing the growth of and leakage from fragile, leaky blood vessels growing under the retina. By limiting the growth of the abnormal blood vessels under the macula, this treatment 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.
People with wet AMD often need multiple treatments to get the full benefits of the therapy.
By sealing the leaky blood vessels, it slows down:
√ The buildup of fluid under the retina
√ The growth of scar tissue and the abnormal membrane under the retina, both of which damage the cells in the macula.
√ Central vision loss
Some experts think that this therapy may be more effective and less destructive than laser surgery. Laser treatment almost always causes some immediate, permanent central vision loss (a central blind spot) because it uses a hot laser and damages some healthy tissue in the process.
PDT may be better able to target the blood vessels without damaging the nerve cells in the retina and macula. It uses a low power or cold laser which does not burn healthy eye tissue. Visudyne is a dye that is injected. The dye moves to the blood vessels in the macula. Laser light is then shone into the eye, which activates the Visudyne and causes it to create blood clots that block the abnormal blood vessels.
The laser activates the drug in a targeted area of the eye. This produces a reaction that destroys abnormal, leaky blood vessels without hurting the surrounding tissues.
The procedure is typically performed in a doctor's office on an outpatient basis. You will be unusually sensitive to light for 5 days following Visudyne therapy, so preparing for treatment is key. Visudyne medicine makes your skin and eyes more sensitive to light. After treatment, you should avoid direct sunlight for 2 to 5 days and, when outdoors, wear special dark sunglasses to protect your eyes.
Your eyecare specialist will give you a list of instructions to follow before and after therapy to minimize the risk of complications.
What happens during treatment:
1. The light activated dye is injected into the bloodstream, usually through a vein in the patient's arm. The drug is quickly absorbed by the abnormal blood vessels in the back of the eye that cause sight loss in the wet form of AMD.
2. A short time after the drug has been given, around 15 minutes, a low-energy laser is shone into the affected area of the eye for an exact period of time. This activates the drug and produces a reaction that seals the abnormal blood vessels.
After treatment, the doctor will usually examine the patient's eyes on a predetermined schedule, usually by fluorescein angiography to check for choroidal neovascular leakage (leaking blood vessels). If there is more leakage, therapy should be repeated.
There is no cure for AMD. Verteporfin helps destroy existing abnormal blood vessels that can leak and damage sight.
Studies have shown that patients who complete a full course of photodynamic therapy are more likely to preserve their vision than those who have no therapy.
Visudyne Side Effects
A severe loss in visual clarity occurs in 1% to 4% of those treated with verteporfin. In some cases, vision partially recovers.
Other side effects that may occur include:
√ Temporary visual changes (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).
The effectiveness and long-term consequences are still being studied.
There are certain instructions that need to be followed before and after therapy. They are summarized below:
* Bring to the treatment
a tight-knit, light-colored, long-sleeved shirt
shoes and socks
dark sunglasses, a wide-brimmed hat, and gloves
* Arrange for transportation. Don't attempt to drive yourself home from treatment. Your vision may be blurrier than usual.
* Schedule your follow-up appointment to avoid letting too much time lapse before your exam.
* Wear the wristband the doctor gives you to remind yourself and let others know you have a temporary sensitivity to light.
* Avoid exposure to direct sunlight or bright indoor light, including bright halogen lighting.
* Don't stay in the dark. Exposure to normal indoor light is needed to inactivate the dye in the skin.
* If you must go outside during the first 5 days following therapy, wear
dark, wraparound sunglasses that completely cover your eyes, and
protective clothing that completely covers your skin.
UV sunscreens will NOT protect you from photosensitivity reactions.
* Reschedule any elective (nonemergency) dental or surgical procedures that fall within 5 days of your PDT.
* Call your doctor immediately with any questions, concerns, or problems (such as a sudden decrease in vision, or pain at the injection site).
The effect of PDT in slowing the progress of wet 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.
Classic AMD Patients Benefit
Dry AMD patients do not benefit from it because they have not developed these leaky blood vessels and the treatment may not work for many wet age-related macular degeneration patients. Patients who will benefit from this treatment are those who have new blood vessel growth (neovascularization) under the retina in a well defined, distinctive pattern known as "predominantly classic."
About 40-60 percent of new wet AMD patients have this form of macular degeneration, according to Novartis, the company that markets Visudyne (QLT Inc. developed it).
How well the treatment works depends on where and how the abnormal blood vessels are growing beneath the retina.
1. Martidis A, Tennant TS (2004). Age-related macular degeneration. In M Yanoff et al., eds., Ophthalmology, 2nd ed., pp. 925–933. St. Louis: Mosby.
2. Arnold J (2006). Age-related macular degeneration, search date March 2005. Online version of Clinical Evidence (15).
3. Treatment of Age-Related Macular Degeneration With Photodynamic Therapy (TAP) Study Group (2001). Photodynamic therapy of subfoveal choroidal neovascularization in age-related macular degeneration with verteporfin: Two-year results of two randomized clinical trials-TAP report 2. Archives of Ophthalmology, 119(2): 198–207.
Macular degeneration treatment breakthroughs come in small "victories." AMD studies often use current therapies but in new and different combinations, such as combining PDT therapy with Lucentis injections or comparing one treatment against another.
1) Combination Lucentis and Ocular Photodynamic Therapy With Visudyne, With Evaluation-Based Retreatment (CLOVER)
2) Transpupillary Thermaotherapy Versus PDT for Treatment of Choroidal Neovascularization in Age-Related Macular Degeneration
3) Bevacizumab and Photodynamic Therapy in Neovascular Age Related Macular Degeneration
4) Efficacy of Ranibizumab(Lucentis) in Combination With Photodynamic Therapy for Wet Age-Related Macular Degeneration
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