Causes of Diabetic Retinopathy


Diabetic retinopathy is a condition, which originates from complications that arise in diabetes mellitus sufferers and could potentially affect anyone with diabetes, regardless of type. It is one of the foremost and major causes of poor vision in the UK. It usually affects those who have had long standing diabetes, although those relatively new to the condition are not completely immune. If retinopathy goes undetected and untreated, it can ultimately lead to extremely severe loss of vision and eventually complete blindness.

It culminates essentially from an excess of blood sugar, (or glucose) levels due to your body’s inability to sustain it at an ideal level. This is caused, as are all forms of diabetes mellitus, from the pancreas’ inability to produce a sufficient amount of insulin, or an inadequate form of insulin, which is devoid of the ability to satisfy the body’s requirements. This in turn leads to problems with the metabolism and an increase in sugar levels in the blood stream. Diabetes currently affects 2.3 million people in the UK alone and all are at risk of retinopathy. Those who have had diabetes longer than 25 years will most likely have some form of retinopathy, even if this is just a very early onset. A study carried out by the National Eye Institute revealed that around 40-45% of people with diabetes have experienced a stage of retinopathy in America. Patients should discuss haemoglobin A1C levels with their doctor. Ideally this should be below 7 and will aid in the prevention of retinopathy onset.

Haemoglobin A1C levels are directly affected by blood glucose levels. Red blood cells are made from haemoglobin. They can be used to transport glucose around the body and, as glucose sticks to them, they become glycosylated haemoglobin, or haemoglobin A1C for short. Therefore, the more glucose in the blood, the more haemoglobin A1C will be present. This is how your doctor will test your blood sugar levels and has proved to be one of the most effective ways of checking whether or not your diabetes is under control. Because the red blood cells live for around eight to twelve weeks, it is possible to test how your glucose levels have been in this time frame. If your diabetes is generally in control and your A1C levels are below 7, then you are only required to take the tests every 3 - 6 months. Any higher than this and the checks will be more frequent and you are expected to attempt to lower the levels. This is also dependent on your general health and whether or not you take insulin.

Retinopathy therefore, can affect your vision in several different ways. Primarily, it is caused by a deterioration of blood vessels, (or capillaries) in the retina. The retina is comprised of light sensitive tissue at the back of the eye and is the component, which keeps our vision in focus, similar to that of a camera lens. It also retains the cells required for vision and the macula, which is the main focus point within the retina and allows us to focus in detail, for example on smaller, more acute things like small print in books. This means that should there be any damage to the macula, it will affect our ability to focus, which is primarily the cause of blurred vision.

As it is for the most part a product of long term diabetes, the longer you have been diagnosed with diabetes, the more chance you are at risk of developing the condition. Because it is caused by a constant corrosion from the high glucose levels, those who have been exposed to it longer will have had longer to contract diabetic retinopathy. The deterioration of the blood vessels begin firstly by breaking and leaking due to the constant decay as a result of the sugar levels. From this, they can easily become blocked, reducing the cohesion of blood flow to the retina. As a result of constant and interminable wear and tear to the eyes, it can eventually lead to haemorrhages. These are identified by your doctor as specks of blood within the eye, but it can also contribute to oedema; a swelling of the retina.

Blocked vessels can similarly contribute to a lack of oxygen, due to deprived blood flow. This can in turn cause abnormal growths to develop in the retina. Because of the leaking and bleeding on the surface of the retina, it is not uncommon that scarring can form, which reduces the quality of peripheral vision. There are other factors, which can encourage retinopathy. For example, since it is caused by increase in blood sugar levels, attempting to maintain them at a healthy rate or to reduce them will slow its development. Other things such as high levels of triglyceride fats within the blood stream or high blood pressure can also contribute to the speed of its severity. It additionally puts at risk pregnant women who already have diabetes and who are more susceptible, but not those who have contracted diabetes directly through pregnancy.

Despite having numerous risks, the dominant effect of retinopathy and the one in which it is usually associated with it, is vision loss and blindness. However, you must also consider that diabetes mellitus can affect your other organs, such as the heart and kidneys. It is also recommended that you have checks for other problems that diabetes and an exposure to high glucose levels can cause. You should also check the causes and symptoms of other such conditions in order to maintain your overall general health and not just your eyesight.

In regards to vision, diabetes does not solely cause retinopathy. It can also cause glaucoma. This is when a build up of fluid within the eye causes the retina to be placed under heavy pressure. Cataracts are also a cause for concern, however, they largely affect those above the age of 60 and can be caused by other external factors, such as over exposure to ultra violet light from the sun. It creates a clouding over the eye reducing vision and can be treated with surgery.

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