Age Related Macular Degeneration
Put simply, as we get older, delicate cells around the macular become damaged and eventually stop working.
So, what is the macular? Imagine that your eye is like a camera. There is a lens and an aperture (an opening) at the front, which both adjust to bring objects into focus on the retina at the back of your eye. The retina is made up of a delicate tissue that is sensitive to light, rather like the film in a camera.
The macula is found at the centre of the retina where the incoming rays of light are focused. The macula is very important and is responsible for:
- What we see straight in front of us
- The vision needed for detailed activities such as reading and writing
- Our ability to appreciate colour
Because macular degeneration is an age-related process it usually involves both eyes, although they may not be affected at the same time. With many people the visual cells simply cease to function, like the colours fading in an old photograph – this is known as ‘dry’ degeneration.
Sometimes there is scarring of the macula caused by leaking blood vessels and this is called disciform maculopathy.
Children and young people can also suffer from an inherited form of macular degeneration called macular dystrophy. Sometimes several members of a family will suffer from this, and if this is the case in your family it is very important that you have your eyes examined regularly.
In the early stages your central vision may be blurred or distorted, with things looking an unusual size or shape. This may happen quickly or develop over several months. You may be very sensitive to light or actually see lights that are not there. The macula enables you to see fine detail and people with the advanced condition will often notice a blank patch or dark spot in the centre of their sight. This makes activities like reading, writing and recognising small objects or faces very difficult.
Human ageing process.
Macular degeneration is not painful, and never leads to total blindness. It is the most common cause of poor sight in people over 60 but never leads to complete sight loss because it is only the central vision that is affected. Macular degeneration never affects vision at the outer edges of the eye. This means that almost everyone with macular degeneration will have enough side vision to get around and keep their independence.
If you suspect that you may have macular degeneration or you are a sufferer in one eye and believe it is affecting your second eye, you should contact one of our optometrists who can refer you to the hospital if necessary.
In the practice, we will perform a number of tests using eye drops which will make you feel more sensitive to light and blur your vision. If we have to refer you to hospital, you will undertake different tests including:
Fluorescein angiograms involves taking a series of colour photographs of your retina with bright flashes of light. These photographs give an accurate map of the changes occurring in the macula and help your eye specialist to decide what is the best treatment for you. For the angiogram you will be given a small injection of special dye in your arm which then works its way around to your eye. A series of rapid pictures are then taken with a blue light over the next few minutes. There are few side effects, although some people find that they are dazzled for a while afterwards. You may also notice that the injection has left your skin with a faint yellow tinge from the fluorescein dye but this soon passes as it is excreted in your urine.
- Discform degeneration laser treatment is useful for about 10 per cent of people with disciform degeneration, and this population has a common profile: they reported their symptoms early. This is usually performed as an outpatient appointment.Unfortunately, with most people the areas of degeneration are in the middle of the macula, at its focal point. This means that treatment cannot be given because the scars produced by the laser would make central vision worse rather than better.
- There are also a variety of optical aids which make use of the parts of the retina that are not affected. These range from brighter reading lights and simple magnifying glasses to more sophisticated equipment. We can also refer you to the hospital low vision clinic.
There is a great deal of ongoing research exploring the causes of macular degeneration and how it can be treated. With ‘dry’ degeneration, there have been claims that certain types of medical therapy can halt the condition, but this remains uncertain.
You can find out more from the: Macular Disease Society, PO Box 247, Haywards Heath, West Sussex RH17 5FF
If you have would like to know more about this condition, please contact Ian Cameron.
0131 225 2235