Macular degeneration, often age-related macular degeneration (AMD or ARMD), is a medical condition that usually affects older adults and results in a loss of vision in the center of the visual field (the macula) because of damage to the retina.
Age related macular degeneration (AMD) is the most common cause of visual loss in people over 65 years of age. This disease rarely causes total blindness. It causes loss of reading or fine vision. Treatment can save enough side vision to ensure that you remain independent.
The eye is like a camera. At the front of the eye, the pupil, cornea, and the lens focus the image.
The retina, a light sensitive layer, which lines the back of the eye, receives the image. The image is then sent via the optic nerve to our brain.
This is why glasses do not help us if our poor vision is caused by damage to the retina. Glasses only help the front of the eye to focus the image more clearly.
Your retina works like the film in a camera. It must be healthy to work properly. It cannot take a good picture if it is damaged.
The peripheral retina provides us with our side vision. This enables us to navigate, see landscapes and general shapes. In order to see fine detail, we must use the centre of our retina, the macula.
The macula is the central area of retina that allows us to see any fine detail. It gives us our reading vision and our ability to recognize faces, watch TV, drive a car or sew etc. The very centre of the macula is called the fovea.
The macula is damaged by ageing processes. In the early stages, it shows up as dark dots (pigment clumps) and yellow blobs (drusen). There are two end stages of the disease that are associated with loss of vision. These are called: dry (atrophic) or wet (exudative).
Patches of retina disappear around the centre of the macula.
This is called geographic atrophy and is the most common form of AMD. It is untreatable and eventually involves the fovea, causing slow, progressive loss of reading vision.
This occurs when the barrier which separates the retina from the choroid (the vascular layer beneath the retina) breaks down. Blood vessels grow from the choroid into the retina. The retina provides ideal conditions for the new blood vessels to grow rapidly. New blood vessels are fragile. They bleed, leak fluid and form a mound of scar tissue. Over time, these blood vessels may continue to grow and destroy more vision. Visual loss may be rapid and severe.
New blood vessels can be seen with special photographs called angiograms. Fluorescent yellow dye is injected into your arm and your eye is photographed as the dye passes through the blood vessels in your eye, outlining any abnormalities or leaks. Sometimes another dye test may be required using ICG. This shows the blood vessels in the choroid.
As the name suggests, age is the major risk factor in AMD. There is also a genetic factor in that it tends to run in families. The major preventable risk factor is smoking. Diet may also play a part. The role of vegetable oil is controversial and as yet unproven.
The most sensible policy is to maintain a well balanced diet, including plenty of fresh vegetables, nuts and fish. This will also help to limit the effects of high blood pressure and cardiovascular disease.
Laser treatment is possible in some forms of wet AMD. It aims to preserve as much peripheral retina as possible and prevent severe visual loss by stopping new blood vessels growing. If the new blood vessel can be detected and treated at an early stage, this can significantly increase your chance of avoiding severe visual loss.
However, it is unrealistic to expect to keep your normal reading vision. Laser is a concentrated beam of light. It destroys the leaking blood vessels in an attempt to prevent further damage.
Developed as a result of international trials, Macu-vision™ is a multivitamin and mineral supplement shown to slow down the progression of established AMD.
The use of intravitreal injection of Lucentis or Avastin has completely revolutionized the treatment of macular degeneration over the past two years. These are known as anti-VEGF (vascular endothelial growth factor) substances, which inhibit the abnormal blood vessels which are a feature of WET macular degeneration. Unfortunately they have no benefit for the DRY forms of macular degeneration. They are usually given as a course of three injections at monthly intervals and after the initial course may need to be repeated as needed.
The injections are given in the rooms as an out patient procedure.