The macular is a small and very sensitive region of the retina responsible for clear central vision. Damage to this area over time is known as 'age-related macular degeneration' (AMD) and is characterised by a loss of central vision.
As the disease progresses, it blurs the patient's central vision – creating the illusion of a ‘hole’. This may mean that when the patient looks directly at someone, they are able to see the person's hair and clothes but not their face. Although the precise cause remains unknown, it is thought that exposure to 'blue light' - a type of high-energy visible light emitted by the sun - is an important factor.
The role of the macula is to filter out harmful blue light before it hits the sensitive cells (known as the rods and cones) of the retina. As a person gets older, the risk of AMD increases, particularly when coupled with poor diet, smoking and drinking which can accelerate the onset of the disease.
AMD can take two forms, wet and dry. Wet AMD is caused by the abnormal growth of blood vessels under the macula, this leads to rapid loss of central vision. Wet AMD is considered to be advanced AMD and is more severe than the dry form. Dry AMD, the more common form, occurs when the light-sensitive cells in the macula slowly break down over time. Untreated dry AMD can progress into wet AMD.
According to the National Eye Institute (NEI) at the US National Institutes of Health (NIH), nearly two million Americans have vision loss from advanced AMD, and another seven million with AMD are at substantial risk for vision loss. It is thought that the AREDS vitamin and mineral formulation could save more than 300,000 people from vision loss over the next five years.
For more information, visit the NEI Website.