Macular Degeneration
What is It?
The macula is the part of the retina responsible
for detailed vision and ability to see colours. Macular degeneration
occurs when this area of delicate cells are irreparably damaged.
What Is The Effect On Vision?
Damage in this area disrupts the central vision.
Vision may be distorted and blurry, or in severe cases lost completely.
What Are The Symptoms?
The symptoms depend on the form of the disease.
There are two forms:
• Non Exudative (commonly referred
to as Wet): a gradual deterioration in
sharpness and some distortion
• Exudative (commonly referred
to as Dry): a sudden onset of distortion
of objects and waviness of straight lines
What Is The Difference Between The Two Types?
Dry: is the most
common form and occurs when deposits build up on the macular area
and stop the pigment cells from working. This results in a reduction
in the quality of vision. The condition usually develops and progresses
slowly.
Wet: is
rarer, accounting for about 10% of all AMD cases. It occurs when new
blood vessels grow behind the retina causing bleeding and scarring.
The condition can develop very quickly.
What Causes It?
This is not yet fully understood, but it appears
to be due to a breakdown in cellular metabolism.
Who Is Most At Risk?
Macular Degeneration mostly occurs in senior
citizens. It is therefore commonly referred to as Age Related Macular
Degeneration.
The following factors also have a bearing on its development:
Gender: slightly more common in women
Family
history : there is a genetic link
Smoking:
increases free radical activity
Excessive
sunlight: UV causes cell damage
Poor
nutrition: vitamin and mineral deficiency affects photopigment cell
renewal
Can It Be Tested For?
Both wet and dry forms can be picked up during
a routine examination by analyzing the appearance of the macular area
and performing a central visual field test. In the wet form, however
it may not reveal itself at all, and can often occur very suddenly
in an eye that has previously been deemed to look healthy.
More comprehensive tests such as Fluoroscein Angiograms can be done
at the hospital if Wet AMD is suspected.
What Is the Treatment?
The treatment, if any, depends on the type of
macular degeneration:
• Exudative -
Laser and drug treatment.
• Non Exudative
- no treatment but vision aids such as magnifiers may help
Treatment success is variable and does not usually restore lost vision.
However new treatments are being developed all the time. One of the
newest is PhotoDynamic Therapy (PDT) which involves a light sensitive
drug being injected into the blood stream to identify abnormal blood
vessels growing behind the macula. A laser shone on these vessels
then activates the drug and stops the vessles form growing and causing
further damage. The best results are acheived in the early stages
of disease onset.
Because of the variable success rate, in some areas treatment under
the NHS is not available at all, or is subject to limitations.
Further Information
More information on Macular Degeneration is available by clicking
these links:
http://www.rnib.org.uk/xpedio/groups/public/documents/PublicWebsite/public_rnib003635.hcsp
http://www.nhsdirect.nhs.uk/articles/article.aspx?articleId=399
http://www.macular-degeneration.org/
|
| |
| |
|
 |
| Macular Degeneration
View |
| |
 |
| Normal View |
| |
| |
| |
|
