Macular degeneration age related
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Age Related Macular Degeneration, or ARMD, is a common, chronic eye disorder that affects older people and whose central feature is visual loss and blindness. The onset of the disease occurs around 50 years of age and total blindness usually at around 75 years of age, in people in developed countries. Despite considerable research on the disease the causes remain unknown.

ARMD occurs due to degeneration of the macula, which is located at the center of the retina and is the most sensitive part of it, containing the cones. It is these cones that are responsible for giving us daylight, sharp and central vision needed to do common tasks like reading or moving around. It is because the macula is affected that the central vision is lost in ARMD. The disease, however, causes no pain.

Types of Age Related Macular Degeneration

Macular degeneration is of two types, dry or non-neovascular and wet or neovascular. Dry ARMD accounts for 80% of the diagnosed cases but wet ARMD accounts for 80% of the severely visually impaired cases.

Dry or non-neovascular ARMD: Dry ARMD is an early stage of the disease resulting from aging and thinning of the macular tissues, pigment deposits or both. In dry ARMD, light sensitive cells of the macula gradually break down, slowly blurring the central vision. You will then need more light to see objects.

It is diagnosed as dry ARMD when yellow spots called drusen, formed from the deposits, are observed on the macula. Dry ARMD usually produces a gradual loss of vision, but the condition is not as severe as in wet ARMD. The disease can affect both eyes but vision may be lost in only one eye.

Wet or neovascular ARMD: About 10% of the dry ARMD cases progress to a more severe form of the disease called wet or neovascular ARMD. Neovascularization refers to growth of new blood vessels, which is what happens in wet ARMD. Forming new blood vessels is body’s aberrant way of responding to the degenerating retina’s demand for more blood. These new arteries are formed beneath the retina. They have weak walls which leak blood and fluid to the retina, thus permanently destroying some light sensitive retinal cells, producing dark spots in your vision. This leakage may lead to scarring and central vision loss. With wet ARMD loss of vision can occur quickly.

Signs and symptoms

For dry ARMD the most common early sign is blurred vision. As the macula deteriorates you will less and less. However, in bright light you will see well. With further deterioration of the macula you will see a growing blind spot in the centre of your vision.

In wet ARMD the classic early symptom is straight lines appearing crooked. This happens when the leaking fluid lifts the macula distorting the vision.

For ARMD in general, viewing the Amsler grid, which is a chart containing black lines in a graph pattern, is a surer way to see if you have this disease.

Visiting an eye practitioner is the best way to confirm ARMD. He will often detect early signs of ARMD before the symptoms appear. He will do all the tests including fluorescein angiography, which examines the blood vessels on the retina.

Risk factors in ARMD

Besides older people, whites and female seem to be more prone to ARMD. The disease may be a side effect of some drugs. In some cases it is believed to be hereditary.

Latest evidence suggests that smoking could be a high risk factor. Other risk factors include obesity, high blood pressure and lighter eye color. However, conclusive evidence is lacking about these risk factors.

Treatment

There is no FDA approved cure for ARMD. There are some treatments which slow down the progress of the disease or improve the vision. Treatment depends on whether it is dry or wet ARMD.

For dry ARMD, a study conducted by a major research institute has produced strong evidence that vitamin A, C and E may slow down the progress of the disease, if not prevent it. The study also concluded that high doses of certain nutritional supplements could reduce the chances of progression by 25%. Some doctors advise sun glasses for dry ARMD patients as protection against ultra violet light.

For wet ARMD, drugs like the FDA approved Lucentin and Macugen used with Photo Dynamic Therapy have been shown to stop or slow down the formation of new blood vessels. Lucentis has also been able to improve vision in some cases.

 
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