Age-related macular degeneration — also called macular degeneration, AMD or ARMD — is the deterioration of the macula, which is the small central area of the retina of the eye that controls visual acuity.
The health of the macula determines our ability to read, recognize faces, drive, watch television, use a computer, and perform any other visual task that requires us to see fine detail.
Macular degeneration is the leading cause of vision loss among older population, and due to the aging of the European population, the number of people affected by AMD is expected to increase significantly in the years ahead.
AMD is most common among the older white population, affecting more than 14 percent of white Americans age 80 and older.
Wet And Dry Forms Of Macular Degeneration
There are two main types of age-related macular degeneration:
Dry form. The "dry" form of macular degeneration is characterized by the presence of yellow deposits, called drusen, in the macula. A few small drusen may not cause changes in vision; however, as they grow in size and increase in number, they may lead to a dimming or distortion of vision that people find most noticeable when they read. In more advanced stages of dry macular degeneration, there is also a thinning of the light-sensitive layer of cells in the macula leading to atrophy, or tissue death. In the atrophic form of dry macular degeneration, patients may have blind spots in the center of their vision. In the advanced stages, patients lose central vision.
Wet form. The "wet" form of macular degeneration is characterized by the growth of abnormal blood vessels from the choroid underneath the macula. This is called choroidal neovascularization. These blood vessels leak blood and fluid into the retina, causing distortion of vision that makes straight lines look wavy, as well as blind spots and loss of central vision. These abnormal blood vessels and their bleeding eventually form a scar, leading to permanent loss of central vision.
Most patients with macular degeneration have the dry form of the disease and can lose some form of central vision. However, the dry form of macular degeneration can lead to the wet form. Although only about 10% of people with macular degeneration develop the wet form, they make up the majority of those who experience serious vision loss from the disease.
It is very important for people with macular degeneration to monitor their eyesight carefully and see their eye doctor on a regular basis.
Causes of macular degeneration
The exact cause of macular degeneration isn't known, but the condition develops as the eye ages.
Age-related macular degeneration (AMD) is caused by a problem with part of the eye called the macula. The macula is the spot at the centre of your retina (the nerve tissue that lines the back of your eye).
The macula is where incoming rays of light are focused. It helps you see things directly in front of you and is used for close, detailed activities, such as reading and writing.
Increased risk
It's unclear what triggers the processes that lead to AMD, but a number of things increase your risk of developing it. These are described below.
Age
The older a person gets, the more likely they are to develop at least some degree of AMD.
Most cases start developing in people aged 50 or over and rise sharply with age. It's estimated 1 in every 10 people over 65 has some signs of AMD.
Family history
AMD has been known to run in families. If your parents, brothers or sisters develop AMD, it's thought your risk of also developing the condition is increased.
This suggests certain genes you inherit from your parents may increase your risk of getting AMD. However, it's not clear which genes are involved and how they're passed through families.
Smoking
A person who smokes is up to four times more likely to develop AMD than someone who's never smoked.
The longer you've been smoking, the greater your risk of getting AMD. You're at even greater risk if you smoke and have a family history of AMD.
Treating macular degeneration
There's currently no cure for either type of age-related macular degeneration (AMD), although vision aids and treatments may help.
Dry AMD
With dry AMD, the deterioration of vision can be very slow. You won't go completely blind, as your peripheral (side) vision shouldn't be affected.
Help is available to make tasks such as reading and writing easier. Getting practical help may improve your quality of life and make it easier for you to carry out your daily activities.
You may be referred to a low vision clinic. Staff at the clinic can provide useful advice and practical support to help minimise the effect dry AMD has on your life. For example, you may wish to try:
Diet and nutrition
There's some evidence a diet high in vitamins A (beta-carotene), C and E – as well as substances called lutein and zeaxanthin – may slow the progression of dry AMD, and possibly even reduce your risk of getting wet AMD. Talk to an ophthalmologist about whether these could help you.
Foods high in vitamins A, C and E include:
Leafy green vegetables are also a good source of lutein, as are peas, mangoes and sweetcorn.
There's no definitive proof eating these foods will be effective for everyone with dry AMD, but this type of healthy diet has other important health benefits, too.
Dietary supplements are also available, some of which claim to specifically improve eye health. However, these are rarely prescribed on the NHS so you'll usually have to buy them. It's important to check with your GP before taking supplements as they may not be suitable for everyone.
Wet AMD
The two main treatment options for wet AMD are:
