AMD is an eye condition that affects a very small part of the retina located at the back of the eye, called the macula. The macula is about the size of a pin head and its highly-sensitive cells provide our detailed central vision.
With AMD, changes in the macula leads to problems with central vision, for example, when reading, the page may appear distorted then, over time, a blank or dark patch may appear in the middle of your vision.
You might notice that your vision isn’t as clear as it used to be. Or you may have difficulty reading smaller print, even with reading glasses, while some people complain that straight lines become distorted or wavy.
The exact cause of AMD is currently unknown but risk factors include:
AMD can be split into 2 main types: ’Wet’ and ‘Dry’.
NB: AMD is not related to wet (watery) or dry eyes.
Dry AMD the most common form of AMD and develops very slowly. In fact, Dry AMD may take many years to reach its end stage, when it leaves a dark / blank patch in the central vision.
However, a small percentage of those with Dry AMD will also develop Wet AMD so if you are affected by this condition, you must report any changes in your vision as soon as possible to your Consultant or Optometrist
Around 10-15 % of people with AMD have Wet AMD, which, for a small percentage of people, will have started as Dry AMD.
This condition occurs when the cells in the macula stop functioning correctly and new blood vessels develop (neo-vasularisation) in an attempt to fix the problem. Unfortunately, these blood vessels start to leak fluid into the macula – hence the term ‘Wet’. This process causes damage to the macula in the form of scar tissue, resulting in permanent blurring of your central vision.
This condition can happen quickly so needs to be assessed and treated as soon as possible to reduce the amount of scar tissue that develops.
Like a routine eye test, your eyes will need to be examined under a special microscope, normally after dilating drops have been applied to enlarge your pupils.
An OCT or Optical Coherence Topography will measure and map the layers of the retina to provide the Edinburgh Eye Surgeon with the detail and information required.In some cases, a Fluorescein Angiogram will be required.
This involves injecting a small amount of yellow dye into the back of your hand and as the dye flows through the veins, it allows the vessels at the back of the eye to be photographed.
Treating Wet AMD
In recent years, medications have been developed to treat Wet AMD called Anti-VEGF.
These medications interfere with the release of the chemical which encourages more vessels to grow, preventing further loss of vision. These medications have a high success rate in preventing further visual loss and, in many cases, improve vision.
Anti-VEGF is injected into the vitreous of the eye, which is the jelly substance in the middle of the eye.
Treating Dry AMD
Unfortunately, there is no treatment for Dry AMD at the moment, although studies have revealed that higher doses of vitamin A, C and E, the minerals copper and zinc and a micro-nutrient called lutein may slow down the progression of this condition.