Age-related macular degeneration (AMD) is the leading cause of vision loss in the U.S., with more than 13 million Americans showing some sign of the disorder. AMD is usually a slow, but variably progressive disease that causes a reduction in central vision – the vision you need for close work like reading a newspaper. It is most common in people over the age of 65. Age-Related Macular Degeneration occurs in two forms. The most common form of AMD is Dry AMD. Drusen, tiny yellow deposits, develop beneath the macula and signal degeneration and thinning of nerve tissue. Wet AMD is less common but requires immediate medical attention to preserve central vision. About 10% of cases of dry macular degeneration develop into the wet form of AMD. Abnormal blood vessels grow beneath the macula leaking blood and fluid onto and underneath the retina.
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The macula is a very small portion of the retina that is responsible for your central vision. About the size of a pencil eraser, the macula is loaded with photoreceptors that enable you to see anything that requires focused vision whether it is reading, sewing, computer work, watch television, or anything else. Tissue damage caused by AMD distorts part of the central image that your eye transmits to your brain.
Most people with AMD do not experience total loss of vision. It is the central vision used for up-close tasks that is lost. Regular eye exams can detect early signs of AMD. More extensive testing such as angiography can also be utilized to aid in detection. Newer technology and research has helped physicians halt or slow progression of retinal changes in AMD patients.
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Recently, the Food and Drug Administration approved a new drug called Macugen for the treatment of wet age-related macular degeneration. The wet form of AMD causes sudden severe vision loss due to the invasion of the macula by leaking, fragile blood vessels. The exact reason why these blood vessels grow is unclear, but is believed to be related to a protein secreted in the retina. Macugen works by blocking this protein, thereby preventing the blood vessel growth.
Macugen is injected into the cavity of the eye (vitreous) by an ophthalmologist and is slowly absorbed into the bloodstream. The injection is given every six weeks for one year. After the first year, your ophthalmologist will discuss the benefit of continuing the injections into the second year. You should not receive Macugen if you have an eye or eyelid infection. Tell your doctor if you are experiencing any eye discharge, itching, burning or redness
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Photo-Dynamic Therapy is another treatment used to help manage the “wet” form of macular degeneration. Treatment is accomplished with the use of an intravenous injection of a light sensitive medication called Visudyne®. Once injected, applying a low-powered laser beam to specific areas of the macula where the lesion is located activates the medication. The activated Visudyne® then begins to destroy the abnormal vessels to prevent them from further leaking. Usually, multiple treatments are needed. Unlike traditional laser photocoagulation, PDT does not cause surrounding tissue damage. PDT usually does not restore vision already lost. The expectation is to halt further vision loss from the disease. Preservation of the existing sight in the affected eye is the goal of treatment. PDT does not benefit all patients with wet macular degeneration, and certain criteria need to be met before treatment can be administered.
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In 2001, the National Eye Institute released its finding of a large clinical trial of high doses of Vitamin C, E, and Beta Carotene, along with Zinc used for patients with AMD. This study statistically demonstrated the benefits of these supplements for patients with moderate to severe AMD. The study did not statistically prove that patients with only minimal changes from macular degeneration benefit from these supplements. The use of nutritional supplements for AMD is a decision made by the eye doctor, patient and primary physician. In view of previous studies, Beta Carotene should not be used by recent ex-smokers or smokers due to the potential increased risk of lung cancer.
These supplements are commercially available and approximate the nutrients’ studies. Unfortunately, diet and multiple vitamins do not approach adequate levels of these nutrients. Always check with your doctor before starting any new supplements.
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Wear glasses or sunglasses with UV 100 protection.
Keep your blood pressure under control.
Stop smoking. Smoking increases the risk of developing AMD – 9 times more likely to
occur than with non-smokers.
East plenty of green, leafy vegetables.
What is Diabetic Retinopathy?
Within the structure of the eye, there is a very delicate tissue that lines the inside of the eye. This fragile lining is called the retina. The retina receives light and transmits images to the brain. Diabetes causes damage to small blood vessels throughout the body, including the retina. In diabetic retinopathy, damage from deteriorating blood vessels can cause visual problems.
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sDuring a dilated eye examination, the doctor will be able to look into the back of the eye to monitor the condition of the blood vessels. With diabetes, leaking or bleeding vessels may be visible even before the patient notices any effect on their vision. Blurry vision may indicate a swelling in the retina. When bleeding occurs, vision may become very cloudy or be completely lost.
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SYes, there are two types of diabetic retinopathy.
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SThis is caused by hemorrhages from the retinal blood vessels. Some of the smaller blood vessels narrow or even close, while others enlarge and form balloon-like sacs. When these vessels leak, they cause swelling and the formation of deposits called exudates. Any or all of these changes can cause decreased vision.
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This starts out like NPDR. Closed blood vessels and the development of new abnormal blood vessels cause PDR. When these new, fragile vessels form, they grow on the retina’s surface or in the vitreous gel. The gel is a substance that fills the inside of the eyeball. If one of these new vessels leaks or breaks, the leakage enters into the vitreous gel. The new vessels are also associated with scar tissue that can pull on the retina causing wrinkling and detachment.
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During the dilated eye examination, the physician is able to see the vessels and will determine if additional testing should be ordered. Optical coherence tomography (OCT) is a non-invasive scanning LASER that produces a high definition map of the retina. It is used to evaluate the swelling associated with diabetic retinopathy. Another test, called fluorescein angiogram, is often times ordered so that careful monitoring of the eye can be obtained. This test involves injecting a water-soluble dye into a small vein on the hand or arm and taking a series of high-speed, specially filtered photographs as the dye travels through the blood vessels in the retina. These results help to evaluate the areas of leakage or new vessel formation. They also are valuable if it is determined that a laser procedure is needed.
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Today the mainstay of treatment involves laser surgery. This procedure utilizes a powerful beam of laser light energy on the retina. Selective destruction and sealing blood vessels of damaged areas of the retina can be achieved. Laser treatment is often helpful in maintaining the present vision and lowering the chance of future vision loss for as long as possible. This treatment involves no incisions and is often performed at the doctor’s office.
Medication can also be used to treat diabetic retinopathy. The use of Anti-VEGF agents given inside the eye by your doctor have become an important treatment option for more advanced retinopathy cases. These medications work by blocking a substance known as vascular endothelial growth factor (VEGF), a substance that contributes to the growth of abnormal blood vessels and leakage. Steroid injections can also be used.
Careful preparation of the eye prior to injection, including anesthetic and disinfecting drops, aid in preventing complications related to the injection. These medications can be given repeatedly depending on the response and may improve how well you see.
A vitrectomy is a surgical procedure that is performed when bleeding has occurred in the vitreous gel, or if scar tissue is pulling on the retina. This type of surgery is usually performed after other methods of treatment have already been attempted.
Yearly dilated eye exams are recommended to all with diabetes. More frequent monitoring may be required if retinopathy is present. The best treatment of diabetic retinopathy is strict control of your blood sugar. As well controlled blood sugar and A1C levels can significantly reduce the risk of long-term vision loss.
