Age-related macular degeneration (AMD) is a breakdown or deterioration of the eye’s macula. The macula is a small area in the retina — the light-sensitive tissue that lines the back of the eye. The macula is responsible for central vision and allows an individual to see the fine details clearly.
Although macula makes up only a small part of the retina, it is much more sensitive to detail than the rest of the retina. The macula is what allows a person to thread a needle, read small print, and read street signs. The peripheral retina gives you side or peripheral vision.
Macular Degeneration occurs in older people as part of the body’s natural aging process. There are different kinds of macular problems, but the most common is age-related macular degeneration.
In adults over the age of 50, Age-Related Macular Degeneration is one of the main causes of severe vision loss. According to the Centers for Disease Control and Prevention, an estimated 1.8 million people have AMD and another 7.3 million are at substantial risk for vision loss from AMD. Women are more prone to AMD than men.
AMD is a loss of central vision that can occur in either dry (atrophic) form or wet (exudative) form due to the changes in the macula.
Dry AMD occurs due to the damaged caused to cells of the macula by accumulation of deposits called drusen (yellow deposits beneath the retina). It’s the least serious and most common type of AMD diagnosed in around 9 out of 10 AMD cases.
Vision loss is slow, occurring gradually, over the years. It is estimated that about 1 in 10 people with dry AMD develop wet AMD.
Wet AMD – sometimes called neovascular AMD – develops when abnormal blood vessels form underneath the macula and damage its cells.
Wet AMD is more serious than dry AMD. Without treatment, vision can deteriorate within days.
Macular Degeneration is due to the inability of the part of the eye responsible for central vision (the macula) to function as effectively as it used to.
Causes of AMD
Factors responsible for macular degeneration are not clearly known, and research into the understanding of causative factors for AMD is limited. At this juncture, what remains known about AMD is the complex nature of its causes that include both environment and heredity.
Risk factors for AMD include:
- Age is a major risk factor for AMD.
- Smoking is known to double the risk of AMD.
- Family history and Genetics put people at a greater risk of AMD. Researchers have identified nearly 20 genes increases the risk of developing AMD. Many more genetic risk factors are suspected.
- AMD is influenced by so many genes plus environmental factors such as smoking and nutrition.
There are currently no genetic tests that can diagnose AMD, or predict with certainty who will develop it.
Stages of Macular Degeneration
There are three stages of AMD:
• Early AMD is a stage in which most people do not experience vision loss, necessitating regular eye examination, more so if a person has more than one risk factor. In early AMD, there is the presence of medium-sized drusen.
• Intermediate AMD is marked by some vision loss, but mostly without any noticeable symptoms. A comprehensive eye exam with specific tests will look for larger drusen and/or pigment changes in the retina.
• Late AMD is a stage where vision loss has become noticeable.
Symptoms and Diagnosis of AMD
In its early stages, the following signs of macular degeneration can go unnoticed.
· Gradual loss of ability to see objects with clarity
· Objects seem distorted in shape
· Appearance of straight lines as wavy or crooked
· Loss of clarity in color vision
· A dark spot in the center of vision
Macular degeneration related central vision loss cannot be restored but low-vision devices, such as telescopic and microscopic lenses, can maximize existing vision.
Detection of AMD
The early and intermediate stages of AMD usually start without symptoms. Only a comprehensive dilated eye exam can detect AMD. The eye exam may include the following:
- Visual acuity test consists of an eye chart that measures how well a person sees at distance.
- Dilated eye exam involves placing drops in the eyes to widen or dilate the pupils to get a better view of the back of the eye. A special magnifying lens is then used to look at the retina and optic nerve for signs of AMD and other eye problems.
- Amsler grid detects changes in the central vision which is likely to cause the lines in the grid to disappear or appear wavy – a sign of AMD.
- Fluorescein angiogram involves injecting a fluorescent dye into the arm by an ophthalmologist. Pictures are taken as the dye passes through the blood vessels in the eye, making it possible to see leaking blood vessels, occurring in a severe, rapidly progressive type of AMD. In rare cases, complications such as nausea or more severe allergic reaction, arising due to the injections can possibly occur with this examination.
- Optical coherence tomography involves the use of light waves to achieve very high-resolution images of any tissues that can be penetrated by light—such as the eyes. After dilation of eyes dilated, patient is asked to rest his head on a chin and hold still for couple of seconds as the images are obtained. The light beam is does not cause any pain.
Reducing your risk
- Stop smoking
- Eat a balanced diet that includes plenty of fruits and vegetables
- Moderately consume alcohol
- Maintain a healthy weight
- Wear UV-absorbing glasses while going out in bright sunlight
Treatment of AMD
Although there is no cure for dry AMD, and it is not possible to restore the loss of central vision, researchers and clinicians believe that there is a link between nutrition and the progression of dry AMD. Appropriate dietary changes and intake of nutritional supplements can slow vision loss.
Researchers have linked eye-friendly nutrients such as lutein and vitamin E, vitamin C, zeaxanthin and zinc in reducing the risk of certain eye diseases, including macular degeneration.
Macular Degeneration treatment in India at Sanjeevan focuses on improving the health of the choroid which is responsible for supply of blood to the retina. For dry macular degeneration our treatment increases the blood flow and oxygenation of the choroid and retina helps to clear and prevent accumulation of the cellular debris called ‘drusen’ which brings about an improvement in the central vision.
In wet macular degeneration our treatment helps in reversing the growth of new blood vessels from the choroid behind the retina thereby avoiding the leaking of exudate and fluid and also avoids hemorrhaging. Our treatment ultimately helps in limiting further degeneration of the macula. We also help control the cholesterol level and hypertension which has been shown in research to be a serious contributor towards age related macular degeneration. We administer certain antioxidant supplements because oxidative stress is also said to be responsible for the development of macular degeneration.