What is diabetes?
About one person in fifty in the UK is affected by diabetes mellitus or “sugar diabetes”. As a result, the body cannot normally cope with starchy foods, sugar and other carbohydrates in the diet (or any food that elevates blood glucose levels).
Diabetes can start in childhood usually by a viral attack. In later life too many starchy foods, sugar and other carbohydrates in the diet usually cause it.
If diet is not strictly adhered to then it will cause complications that affect different parts of the body.
There are two types of diabetes mellitus – one is controlled by insulin injections, and the other by diet or tablets, but they both affect the eyes in the same way (see Starch Study).
If you have diabetes this does not necessarily mean that your sight will be affected, but there is a higher risk. If your diabetes is well controlled by diet then you are less likely to have problems, or they may be less serious. However if there are complications that affect the eyes then this can result in loss of sight.
Why regular eye tests are important
Most sight loss from diabetic retinopathy can be prevented. But it is vital that it is diagnosed early. You may not realise that there is anything wrong with your eyesight, and so regular eye checks are extremely important.
How can diabetes affect the eye?
Your eye has a lens and an aperture (opening) at the front, which adjusts to bring objects into focus on the retina at the back of the eye. The retina is made up of a delicate tissue that is sensitive to light, rather like the film in a camera.
What causes a cataract?
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 specialised part of the retina and it is vital because it enables you to see fine detail and read small print. The other parts of the retina give you side vision (peripheral vision). Filling the cavity of the eye in front of the retina is a clear jelly-like substance called the vitreous humour.
Diabetes can affect the eye in a number of ways. These usually involve the fine network of blood vessels in the retina – hence the term diabetic retinopathy.
Your vision may become blurred for a few days or weeks while your diabetes is first being controlled. This is due to the swelling of the lens of the eye and will soon clear without treatment soon after the diabetes is controlled.
This can occur in two forms:
The most serious diabetic eye condition involves the retina and is called diabetic retinopathy.
Background diabetic retinopathy
This condition is very common in people who have had diabetes for a long time. Your doctor may be able to see abnormalities in your eyes, but there is no threat to your sight.
There are two types of diabetic retinopathy that can damage your sight. Both involve the fine network of blood vessels in the retina. They are described below.
This happens when the blood vessels in the retina start to leak.
Proliferative diabetic retinopathy
Sometimes diabetes can cause the blood vessels in the retina to 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 jelly. 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. When the retina is pulled out of position this is called retinal detachment.
With treatment most sight-threatening diabetic problems can be prevented if caught early enough.
Most sight-threatening diabetic problems can be prevented by laser treatment if it is given early enough. It is important to realise however that laser treatment aims to save the sight you have – not to make it better. The laser, a beam of high intensity light, can be focused with extreme precision. So the blood vessels that are leaking fluid into the retina can be sealed.
If new blood vessels are growing, more extensive laser treatment has to be carried out. In eight out of ten cases laser treatment causes the new blood vessels to disappear. It can leave you worse off in the other 20% of cases.
Most sight-threatening diabetic problems can be prevented by diet, nutrition and Micro-current stimulation. If you have already had laser treatment then you may not get the recovery a well as someone who has not had laser. The critical thing is to follow the diet in the action plan.