Diabetes can cause a range of sight problems, including blurred vision or loss of vision, which without treatment can lead to blindness. These problems occur because persistently raised blood glucose levels damage blood vessels in the eye.
The most important sight problem that occurs in people with diabetes is called ‘diabetic retinopathy’. This results from damage to blood vessels that supply blood to the retina, the light-sensitive tissue at the back of the eye. In diabetes, these blood vessels can become blocked and leaky, causing bleeding (haemorrhaging) inside the eye. This prevents light passing through the eye and on to the retina, reducing vision. In addition, as damaged blood vessels form scars within the eye, the retina is pulled and can become detached from the back of the eye, potentially causing blindness.
People with diabetes can reduce the risk of developing sight problems by keeping their blood glucose within a target range. High blood pressure can also damage blood vessels in the eye, and so keeping blood pressure at a relatively normal level (below 130/80 mm/Hg) will help reduce the risk to eyesight.
When first diagnosed with diabetes, an eye examination will be conducted as part of the initial assessment, and then repeated annually if there are no signs of diabetes-related complications, or more frequently if there is evidence of significant retinopathy. This examination is not the same as a routine sight test performed at the optician’s, although several of the standard tests are included. To check the eyes for retinopathy, a trained healthcare professional will take a photograph of the back of the eyes. Eye drops are given beforehand to ensure the retina is visible. These can cause a short-term blurring of vision, and the person must not drive for a period following the procedure. In Lambeth and Southwark, eye examinations for people with diabetes are conducted by the Diabetes Eye Complication Screening service.
Eyesight changes, including blurred vision or seeing spots or ‘floaters’ should be reported to a member of the healthcare team as soon as they occur. Remember that once vision is lost, it may not be possible to restore sight to its previous level.
The NHS National Screening Programme for Diabetic Retinopathy aims to reduce the risk of sight loss among people with diabetes by the prompt identification and effective treatment of sight threatening diabetic retinopathy.
Download information from the National Diabetic Retinopathy Screening Programme:
Diabetic Retinopathy: The Facts (in pdf format)
Eye Screening for People With Diabetes: The Facts (in pdf format)
Note these files are in Adobe Acrobat pdf format. If you have not installed and configured Adobe Acrobat Reader on your system, a free download is available from Adobe.