What is Age-related macular degeneration?
About the macula
The eye is shaped like a ball. The pupil is the opening which allows light to enter the eye. Behind the pupil is the lens which focuses the light onto the retina at the back of the eye. The retina converts the light into images and sends them to the brain. Now we can recognize what we see. A small area at the very centre of the retina is called the macula.
The macula is very important and is responsible for what we see straight in front of us, allowing us to see fine details for reading and writing, as well as our ability to see colour.
About macular degeneration
Sometimes the cells of the macula become damaged and stop working for different reasons.
If it occurs later in life, it is called "age-related macular degeneration", also often known as AMD.
There are two types of macular degeneration or AMD, usually referred to as "wet" and "dry".
"Dry AMD" is the most common form of the condition. It develops very slowly causing gradual loss of central vision. Many people find that vision slowly deteriorates by gradual central blurring and that the colours fade away like the colours fading in an old photograph. There is no medical treatment for this type. However, magnifiers can be helpful with reading and other small detailed tasks.
"Wet AMD" results in new blood vessels growing behind the retina. This causes bleeding and scarring, which can lead to sight loss. "Wet AMD" can develop quickly and sometimes can be treated successfully at an early stage. It accounts for about 10 per cent of all people with AMD
Both "wet" and "dry" AMD usually involve both eyes, although one may be affected long before the other. This sometimes makes the condition difficult to notice because the sight in the "good" eye is compensating for the loss of sight in the affected eye.
AMD is not painful and the most common cause of poor sight in people over 60. Very rarely AMD leads to complete sight loss because only the central vision is affected. This means that almost everyone with AMD will have enough side (or peripheral) vision to get around and keep his or her independence.
Causes of AMD
At the moment the exact cause of AMD is not known. However there are a number of risk factors which have been identified :
- Age - AMD is an age-related condition so growing older makes the condition more likely.
- Gender - Women seem more likely to develop macular degeneration than men.
- Genetics - There appear to be a number of genes which can be passed on through families which may have an impact on whether someone develops AMD or not.
- Smoking - Smoking has been linked by a number of studies to the development of AMD. It has also been shown that stopping smoking can reduce the risk of AMD developing.
- Sunlight - Some research suggests that lifetime exposure to sunlight may affect the retina. It is a good idea to wear sunglasses to protect the eyes.
- Nutrition - Research suggests some vitamins and minerals can help protect against AMD.
Although nothing can be done about age, gender and the genes we inherit, it is possible to control the other more environmental factors that seem to be linked to AMD. Protecting your eyes from the sun, eating a well balanced diet with plenty of fresh fruits and vegetables and stopping smoking may all help to delay the progress of AMD.
Symptoms of AMD
In the early stages your central vision may be blurred or distorted, with objects looking an unusual size or shape and straight lines appearing wavy or fuzzy. This may happen quickly or develop over several months. You may be very sensitive to light or actually see lights, shapes and colours that are not there. This may cause occasional discomfort. AMD is not painful.
Because AMD affects the centre of the retina, people with the advanced condition will often notice a blank patch or dark spot in the centre of their sight. This makes reading, writing and recognizing small objects or faces very difficult.
What to do if you think you have macular degeneration?
If you suspect that you may have AMD but there are no sudden symptoms, you should see your optometrist (optician) or family doctor (GP) who will refer you to an eye specialist. If there is a rapid change in vision you should consult your doctor or hospital's Accident and Emergency Department immediately.
If you have AMD in one eye and you start getting sudden symptoms in your other eye, then you should go to your hospital or ask your GP to arrange an emergency appointment as soon as possible. This will ensure that you get treatment within a few days.