What is Diabetes?
Estimates suggest that nearly one person in twenty five is affected by diabetes mellitus; a condition which means that, due to a lack of insulin, the body cannot cope normally with sugar and other carbohydrates in the diet. Diabetes can start in childhood, but more often begins later in life. It can cause complications which affect different parts of the body, the eye being one of them. There are two different types of diabetes mellitus:
Type 1 diabetes:
Normally occurs before the age of 30 and is controlled by insulin injections.
Type 2 diabetes:
Is generally controlled by diet or tablets, although some people in this group will use insulin injections.
How the eye works
In understanding how Diabetes can affect the eye, it is worth looking at how the eye works. Your eye has a Lens and an aperture (opening) at the front known as the pupil, which adjust to bring objects into focus on the retina at the back of the eye (see above diagram). The retina is made up of delicate tissue that is sensitive to light rather like a film in a camera. It also contains a fine network of small blood vessels. At the centre of the retina is the macula, which is a small area about the size of a pinhead. This is the most highly specialized part of the retina and is vital because it allows you to see fine detail for activities such as reading and writing and also to recognize colours. The other parts of the retina give you side vision (peripheral vision). Filling the space in front of the retina is a clear jelly-like substance called the vitreous gel.
How can diabetes affect the eye?
Diabetes can affect the eye in a number of ways. The most serious eye condition associated with diabetes involves the retina. The three main stages are described next.
Background Diabetic Retinopathy
This condition is very common in people who have had diabetes for a long time. At this stage the blood vessels in the retina are only very mildly affected. They may bulge slightly (micro aneurysmàlight dots), may leak blood haemorrhagesàdark red dots) or fluid (exudatesàyellow spots).
With time, if the background diabetic retinopathy becomes more severe, the macula area may be affected. If this happens, your central vision will gradually get worse. The amount of central vision that is lost varies from person to person. However, the vision that allows you to get around at home and outside (peripheral vision) will be preserved.
Proliferative Diabetic Retinopathy
Sometimes the blood vessels in the retina become blocked. If this happens then new blood vessels form in the eye. This is nature’s way of trying to repair the damage so that the retina has a new blood supply. Unfortunately these new blood vessels are weak. They are also in the wrong place- growing on the surface of the retina and into the vitreous gel. As a result, these blood vessels can bleed very easily and cause scar tissue to form in the eye. The scarring pulls and distorts the retina.
The importance of early treatment.
Although your vision may be good, changes can be taking place in your retina needing treatment. Most sight loss due to diabetes is preventable!
What is the treatment?
Most sight threatening problems caused by diabetic retinopathy can be managed by laser treatment if it is given early enough. It is important to realize, however, that laser treatment can only preserve the sight you have- not to make it better.
Does laser treatment have any side affects?
No treatment is possible without some side effects, although the laser is very bright and causes a temporary reduction of sight which may last an hour or two after the treatment.
If your eye condition becomes more severe, causing retinal detachment and scar tissue, or if the vitreous becomes cloudy due to recurrent bleeding, it may be possible to perform an operation called a vitrectomy. This will involve the vitreous being removed and replaced with a clear solution. It is a highly specialized operation and you should discuss the various options with Mr. Georgiou.
Other ways diabetes can affect the eyes:
Temporary blurring: This may occur as one of the first symptoms of diabetes although it may also occur at any time when your diabetes is not well controlled. It is due to a swelling of the lens of the eye and will clear without treatment soon after the diabetes is brought under control again.
Cataracts: A cataract is a clouding of the lens of the eye, which causes the vision to become blurred or dim because light cannot pass through the clouded lens to the back of the eye.
Important points to remember
Early diagnosis of diabetic retinopathy is vital.
Have an eye examination every year.
Do not wait until your vision has deteriorated to have an eye test.
Most sight threatening diabetic problems can be managed by laser treatment if it is given early enough.
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