People who suffer from diabetes are at risk of developing problems with their eyes Around the time when diabetes can start being detected or if their control is poor patients may suffer from alterations in the optics of their eyes. This presents as blurred vision, correctable by different spectacles. Usually this is temporary and vision normally returns to a stable level once good control is achieved. It is therefore not a significant problem.
The more serious changes are caused by the small blood vessels at the back of the eye becoming leaky. This has a number of different effects; if the leakage is near the macula then it can obstruct the vision (diabetic maculopathy). If this occurs in the periphery, then ultimately new blood vessels grow, these are structurally poor, are likely to leak or develop scar tissue, and can lead to retinal detachments and complete loss of vision.
Luckily only a small percentage of diabetics will develop such sight threatening changes. It is known that the risks of this occurring increase the longer someone has been diabetic and how well they have controlled it.
The good news is that the risk of developing sight threatening disease is drastically reduced if the early changes are detected and if developing beyond a certain level are treated, usually with a laser, to stop progression. This is why all people with diabetes should have at least an annual eye examination. There is now a national screening program for diabetic retinopathy where patients are screened by digital retinal photography. This should also be undertaken annually to enable detection of early changes.