As the eye looks straight ahead, the macula is the point of the retina upon which the light rays meet as they are focused by the cornea and the lens of the eye. Similar to the film in a camera, the retina receives the images that come through the "camera-like" lens. If the macula is damaged, the central part of the images are blocked as if a blurred area had been placed in the centre of the picture. The images around the blurred area may be clearly visible.

Macular Degeneration is damage or breakdown of the macula. The eye still sees objects to the side, since side, or "peripheral" vision is usually not affected. For this reason macular degeneration alone does not result in total blindness. However, it can make reading or close work difficult or impossible without the use of special low vision optical aids.

The retina is the delicate layer of tissue that lines the inside wall of the back of the eye, The macula is a very small area in the centre of the retina. In size, the macula is about the same as a capital "O" in the type of this pamphlet. This small area is responsible for our central "straight ahead" sight used for reading and other fine tasks . Although macular degeneration most often occurs in older people, aging alone does not always result in central visual loss. Nevertheless, macular degeneration is the leading cause of impairment of reading and fine "close-up" vision in Australia.

The most common form of macular degeneration is called involutional macular degeneration. This form accounts for 70 % of cases and is associated with aging. About 10% of macular degeneration falls into a category called exudative macular degeneration. Normally, the macula is protected by a thin tissue that separates it from very fine blood vessels nourishing the back of the eye. Sometimes these blood vessels break or leak and cause scar tissue to form. This often leads to the growth of new abnormal blood vessels in the scar tissue. These newly formed vessels are especially fragile. They rupture easily and may leak. Blood and leaking fluid destroy the macula and cause further scarring. Vision becomes distorted and blurred, and dense scar tissue blocks out central vision to a severe degree.

Other types of macular degeneration are inherited, may occur in juveniles (juvenile macular degeneration) and are not associated with the aging process. Occasionally injury, infection, or inflammation may also damage the delicate tissue of the macula.

If only one eye is affected macular degeneration is hardly noticeable in the beginning stages particularly when the other eye is normal. This condition often involves one eye at a time, so it may be some time before a patient notices visual problems.

Macular degeneration can cause different symptoms in different people. Sometimes only one eye loses vision while the other eye continues to see well for many years. If both eyes are affected, however, reading and close-up work may become extremely difficult. Macular degeneration alone does not cause total blindness. Since side vision is usually unaffected, most people can take care of themselves quite well .

Colour vision may become dim and these other visual symptoms can develop due to macular degeneration.

The examination usually includes a few more tests:

· A grid test in which the patient looks at a test page (similar to graph paper) will be used to check for the extent of sight loss spots.

· A colour vision test will show whether a patient can tell colour differences, and additional tests will help to discover conditions that may be causing the macula to deteriorate .

· Sometimes a fluorescein angiogram is done. The ophthalmologist injects a dye into the patients arm, and then takes photos of the retina and macula. The dye helps to clarify any blood vessel abnormality that might be present.

Macular degeneration can be detected and diagnosed early by an ophthalmologist if periodic eye examinations are part of health care. Early detection is important since people may not realize their vision is impaired. Having your eyes checked is especially appropriate if other family members have a history of retinal problems . For patients with macular degeneration, early diagnosis by an ophthalmologist may prevent further damage or aid the individual in making a visual adjustment with low vision aids .

Treatment of AMD

There is no specific treatment for "dry" AMD, though a multitude of studies is in progress in search of prevention or a cure. As stated earlier, patients with "dry" AMD should be carefully monitored for development of "wet" AMD, and should follow their ophthalmologist's advice regarding management. Treatment for the "wet" form of AMD is aimed at minimizing visual loss and/or minimizing the size of the resulting central "blind spot". Simply put, ophthalmologists may use laser to destroy the CNVM, or abnormal vessels, in the macula. Studies have shown that patients who are treated with conventional laser, which has now been largely abandoned, typically had slightly better vision 2 years following treatment than patients never treated. However, patients with sub-foveal (central) "wet" AMD requiring laser to the fovea (central macula) had a sudden and often disappointing decrease in vision. Unfortunately, a substantial number of patients do present with sub-foveal "wet" AMD.

As such, conventional laser therapy for wet AMD lost most of its luster by the late 1990's and is now reserved for those cases in which the abnormal vessels (CNVM) present far from the center of the macula. A more advanced form of treatment for AMD, known as photodynamic therapy or PDT, has shown excellent success in preventing further deterioration of vision for many patients with "wet" AMD. PDT, which was FDA approved in 2001,involves the intravenous injection of a photosensitizing dye known as Visudyne, which selectively accumulates in abnormal new vessels such as those that develop in "wet" macular degeneration (the CNVM). A red laser, which causes photo-oxidation of the Visudyne, is then shown into the eye for approximately 90 seconds. This destroys the abnormal vessels in the macula without any significant collateral damage. PDT has been quite effective at vision preservation in patients with classic choroidal neovascular membranes (CNVM), however, it is much less effective in the more common occult (difficult to see due to blood or fluid) CNVM's. At present, PDT is still commonly used. However, because the Visudyne dye is expensive and a specialized red laser is required, most patients can only receive the treatment from vitreo-retinal surgeons, thereby making access even more difficult. Furthermore, re-treatments are typically required every few months, at least in the first 24 months following the initial diagnosis.

In December, 2004, the FDA approved the latest treatment available for "wet" AMD, which is known as Macugen (pegaptanib). Macugen is a vascular endothelial growth factor (VEGF) inhibitor. When Macugen is injected into the vitreous humor of the eye, it has the capability of neutralizing a specific vacular endothelial growth factor known as VEGF-A 165. The result is attack of both the angiogenic (vascular growth) response and vascular leakage that are together responsible for the acute visual loss in "wet" AMD. Macugen has demonstrated prevention of visual loss as compared with previous "standard of care" treatments that would include observation of occult CNVM's and PDT with Visudyne for classic CNVM's. Macugen has broad implications for treatment as it has shown efficacy in management of all types of new onset "wet" AMD. In fact, Macugen has shown that it can prevent severe visual loss (defined as loss of three lines of visual acuity on the Snellen eye chart) in as many as 70% of the treated patients during the period of follow-up. Unfortunately, Macugen only has temporary effect and must be re-administered approximately every six weeks. Furthermore, only 6% of patients experienced gains in visual acuity and the average patient in the study still lost visual acuity over the two years of treatment. Nevertheless, Macugen therapy represents a major advance in our armamentarium against AMD. It will prevent severe vision loss in the majority of appropriately selected patients with new onset "wet" AMD and has opened the door to further investigation in the management of this potentially devastating disease.

Protection Against AMD

UV Protection likely plays an important role in prophylaxis against AMD. Beginning at a young age, it is important to begin protecting the eyes from UV light. Look for sunglasses that afford 100% UV protection or prescription eyewear with the same. Realize that eyewear need not be dark to protect one's eyes from UV light. In fact, 100% UV protection can be present in spectacles with virtually clear lenses. Also, consider wearing a brimmed hat to shade the eyes while outdoors.

Nutrition most certainly plays a role in AMD as well. Research suggests that individuals whose diets are rich in leafy green vegetables have less risk of AMD. This is thought to be secondary to the intake of a group of carotenoids (colorful pigments) found in high concentrations in certain leafy green vegetables. These pigments are also present in significant concentrations in the macula itself. These carotenoids, known as lutein and zeaxanthin, are antioxidants, which likely play a role in neutralizing free radicals (charged molecules), produced in the highly metabolically active macula. A recent study sponsored by the National Institutes of Health found that individuals who had the highest consumption of vegetables rich in carotenoids, especially lutein and zeaxanthin, had a 43% lower risk of developing AMD than those who ate these foods the least. Vegetables that are rich in these two carotenoids would include raw spinach, kale, and collard greens.

Nutritional supplements may be beneficial for those people unable to get adequate intake of fruits and vegetables. However, studies are presently unclear as to whether one can achieve the same protection from supplements containing carotenoids that is achieved with consumption of vegetables themselves.

Smoking is a powerful risk factor for loss of vision with AMD. In fact, one study showed that smoking more than doubles the risk of AMD. This study also found that AMD is more than twice as common in people who smoke more than a pack of cigarettes a day, compared with people who do not smoke. Furthermore, the risk remains high even 15 years after quitting. The advice from ophthalmologists, therefore, is to quit smoking if you desire to retain the best possible vision, regardless of your age.

High Blood Pressure must also be controlled, as this is another risk factor for loss of vision with AMD. Patients should seek and follow the advice of their primary care doctors if they have hypertension. Furthermore, patients should limit saturated fats in the diet and keep alcohol consumption to a minimum.

What Supplements Should One Take to Prevent AMD Progression?

Given the findings of these studies, most ophthalmologists have begun to recommend that patients with AMD include an abundance of leafy green vegetables in their diet. Bausch and Lomb, the maker of Ocuvite®, produces supplements specific for patients with macular degeneration, including Ocuvite Extra®, and Ocuvite® Lutein. These products are found in retail stores and pharmacies everywhere. Macular Protect Complete® from Science Based Health, Alcon laboratories ICaps™, and other supplements also contain antioxidant vitamins and zinc in dosages supported by the AREDS study group, along with various doses of other vitamins and minerals, which are beyond the scope of this article. It should be pointed out that supplementation with beta-carotene, a vitamin A precursor, has been shown to increase the risk of lung cancer among smokers. However, whole food based supplementation has not been shown to increase the risk of lung cancer among smokers and, in fact, there is some evidence that whole food based nutrition may decrease the risk of lung cancer in smokers. One study showed that a higher intake of green and yellow vegetables or other food sources of beta-carotene decreased the risk of lung cancer. As such, smokers should exercise caution in consuming any non whole-food based supplement that contains beta-carotene or Vitamin A. Conclusions It is clear from the studies to date that a diet rich in dark, leafy green vegetables will help to decrease an individual’s risk of developing age-related macular degeneration (AMD). It would be wise to include a serving or two of raw spinach, kale, or collard greens in your diet every day to help prevent macular degeneration and/or to help delay progression of the disease once it has begun. If an intermediate degree of AMD has already developed, or an advanced degree of AMD has developed in one eye, studies clearly indicate that dietary supplementation with vitamins E and C, beta-carotene, zinc and copper, in the doses previously mentioned, will help to delay progression of the disease. These antioxidant vitamins are readily available in a number of over-the-counter products including Ocuvite®, ICaps™, and many others. AMD may not be an entirely preventable disease, however, it is certainly prudent for all of us to minimize our risk. How do we do this? Don’t smoke. Be sure your blood pressure is controlled. Consume plenty of dark, leafy green vegetables and consume the recommended antioxidant vitamins and zinc. Finally, if you're over 65 or you've already been diagnosed with AMD, see your EyeMD (ophthalmologist) at least once a year or per his or her recommendations

An ophthalmologist is the medical doctor (MBBS, FRANZCO) who is educated, trained, and licensed to provide total care of the eyes including the diagnosis and treatment of macular degeneration. Total eye care includes performing comprehensive medical eye examinations, prescribing corrective lenses, diagnosing diseases and disorders of the eye and using the appropriate medical and surgical procedures necessary for their treatment. Only an ophthalmologist can provide total eye care.

Low vision optical aids often improve vision for people with macular degeneration. Many different types of magnifying devices are available. Spectacles, hand or stand magnifiers, telescopes and closed circuit television for viewing objects are some of the available resources. Aids are either prescribed by your ophthalmologist or by referral to a low vision specialist or centre. Bright illumination properly directed for reading and close work are often beneficial. Special lamps can also be helpful. Books, newspapers and other items available in large print offer further help.