First off. There is no eye operation that will cure diabetes.

One of the most distressing possible effects of this disease is loss of vision. The procedures available to ophthalmologists are all designed to minimise or postpone the devastating changes that can occur if left untreated.

Long term exposure to high levels of blood sugar can make blood vessels "leaky". Minor changes have very little effect on vision and are not uncommon. Most do not signify major problems. However larger haemorrhages, especially near the centre of vision (the macula) do need treatment to stop them causing serious problems.

The earliest changes are what are known as "micro-aneurisms", very small swellings (like balloons) on the smaller capillaries. These do not need treating, but if present close to the macula or in large numbers, do mean that a closer watch needs to be kept on the eye.

The next stage is when small bleeds occur and cause what are often called "blot" or "dot" haemorrhages.