Age-Related Macular Degeneration (ARMD) is the most common cause of vision loss in people aged over 50, and it's prevalence increases still further with age. It is cuased by the degeneration of the macular, which is the central and most sensitive part of the retina at the back of the eye.
The macula is the part of the retina that allows the eye to see fine details at the centre of the field of vision. Macular degeneration results from a partial breakdown of the retinal pigment epithelium (RPE).
The RPE is the insulating layer between the retina and the choroid (the layer of blood vessels behind the retina). The RPE acts as a selective filter to determine what nutrients reach the retina from the choroid. Many components of blood are harmful to the retina and are kept away from the retina by normal RPE.
Macular pigment is a yellow substance that has powerful anti-oxidant properties and helps protect the retina from the harmful affect of blue light. It is generally accepted that people with low levels of macular pigment are more at risk of developing ARMD in later life unless positive steps are taken to increase the density of macular pigment.
Breakdown of the RPE interferes with the metabolism of the retina, causing thinning of the retina (the DRY phase of macular degeneration). These harmful elements may also promote new blood vessel formation and fluid leakage (the WET phase of macular degeneration).
This disorder results in the loss of central vision only and the peripheral field of vision is always maintained. Macular degeneration may lead to the loss of your ability to read or drive but it does not lead to total blindness.
This illustration is an example of what someone with advanced macular degeneration might see.
Straight lines may become distorted
The central part of the visual field may be missing
Reading may become very difficult
Some people with macular degeneration notice that straight lines in a landscape, such as telegraph poles or sides of a building, appear to be wavy. Other symptoms include blurring of type or a page of print, with dark or empty spaces that may block the centre of the field of vision.
The disease becomes increasingly common amongst people in each succeeding decade after age 50. By the age of 75 almost 15% of people suffer with this condition. About twice more women over the age of 75 are affected with ARMD than men. Other risk factors include family history, cigarette smoking and being Caucasian.
Vision loss caused by ARMD cannot normally be reversed but in some cases treatment may halt or delay the progression of vision loss.
Prevention is always preferable to a cure and regular macular pigment screening is recommended for everyone over 30 years old. Those identified as being at risk may then choose to take proactive steps to help reduce the potential of developing ARMD in future life.
ARMD Video Demonstration
Click on the following icon for a short illustration of the changes that occur in the eye of an ARMD sufferer, and the influence it has on vision (requires Windows Media Player).
The macula is the part of the retina that allows the eye to see fine details at the centre of the field of vision. Macular degeneration results from a partial breakdown of the retinal pigment epithelium (RPE).
