Wet Macular Degeneration
What is Wet Age-Related Macular Degeneration?
Age-related macular degeneration (AMD) is a breakdown of the macula in the eye. The macula is the center part of the retina, the light-sensitive tissue that lines the back of the eye. The macula is the part of the retina that we use for our most detailed vision work, like reading. When someone gets the wet form of AMD, abnormal blood vessels grow underneath the macula. These abnormal blood vessels are called choroidal neovascular (CNV) membranes and can produce tissue swelling, hemorrhage, and scarring. Although the damage to the macula can lead to loss of central vision, peripheral vision is normally preserved.
Who is at risk for AMD?
Computerized photographic tests such as a flourescein angiogram, indocyanine green angiography, and optical coherence tomography help to evaluate the extent of damage from wet macular degeneration.
What Causes Wet AMD?
AMD has many risk factors, including age over 50 years, a family history of AMD, and smoking. Caucasians, especially those with lighter color and blue eyes are at higher risk
What causes wet AMD?
With aging, the layer under the retina thickens and the nutrient supply to the retina is disturbed. In response, Vascular Endothelial Growth Factor (VEGF) is released and abnormally high VEGF causes leaky blood vessels to grow under the retina. When these leaky vessels bleed, scarring and damage occur to the retina.
How is wet AMD diagnosed?
Many times people first realize that they have a macular problem like wet AMD when they notice blurring, distorted lines, or missing spots in the vision. Examination of the retina with specialized lights and lenses after dilation of the pupils can discover signs of AMD. Computerized photographic tests such as a fluorescein angiogram (FA) and optical coherence tomography (OCT) help in evaluating the extent of damage and response to treatment. An FA is done by injecting an orange dye into a vein in the arm and taking special digital photographs of the dye as it flows through the blood vessels in the retina to look for abnormalities. An OCT is a painless computerized scan of the retina that provides a detailed view of the inner retinal structures.
What can be done for Wet AMD?
In the past, lasers were used as a way to stop or slow the bleeding and leaking of abnormal blood vessels in wet AMD. However, these older forms of laser could cause permanent blind spots and the wet AMD would often continue to progress. More recently, Anti-VEGF treatments have almost completely replaced lasers for the treatment of wet AMD. Anti-VEGF medications were developed to remove VEGF, the major factor in abnormal vessel development in wet AMD. These medications must be delivered as an injection in the eye after anesthetic and antiseptic treatment to the eye to make the injection as comfortable and safe as possible. Since the introduction of anti-VEGF medications, many clinical trials have proven their efficacy and superiority to laser. We previously could only hope to reduce the amount of vision lost in wet AMD. Now we see that one third of patients receiving monthly injections may actually regain vision and only one in ten go on to have significant vision loss. Bevacizumab (Avastin), Ranibizumab (Lucentis), and Aflibercept (Eylea) are the most useful drugs we have available today and your retinal consultant will help decide which is right for you.
How frequently do I need Injections?
The Anti-VEGF agents currently available last for 4-6 weeks before their effects fade and a new injection is typically needed. Most clinical trials show that treatment every 4-8 weeks gives the best results. Some patients need more frequent injections and others need less frequent injections. The intervals required by any one patient may change with time. Your doctor will decide with you how frequently you need treatment.
Does the injection hurt?
The procedure is quick and practically pain free for most patients. A sterile lid speculum helps keep the eye open and an antiseptic kills any germs. It is common for the eye to feel irritated and scratchy for a day after the injection. Worsening vision and severe pain, especially if it is not improving after the first day may be signs of an infection after an eye injection and if you have these symptoms you must contact your doctor.
Will I go blind from wet AMD?
With treatment and close follow up, today’s treatments for wet AMD can often preserve good vision for years. Even with the best treatment, it is possible that AMD may progress and lead to significant vision loss. If only one eye is affected by wet AMD, it is possible that they other eye may develop wet AMD at a later time. It is important to monitor both eyes and to follow your doctor’s instructions to maximize your chances of keeping your retinas as healthy as possible. Although in severe cases, patients may lose their center vision from AMD and become unable to read or recognize faces easily, it is very rare for patients to become totally blind or to lose the ability to walk from AMD. Tools, magnifiers, and techniques, called low vision aids, can help many patients with vision affected by AMD lead a more normal life.
An OCT retina scan can show abnormal blood vessels (CNV) under the macula in wet AMD.
A fluorescein angiogram can show areas of abnormal leakage from choroidal neovascular membranes into the macula.
A color photograph showing bleeding in the macula from wet AMD