In a few diabetics changes occur in the blood vessels supplying the light sensitive tissue (the retina) which lines the inner surface of the back of the eye. If the retina becomes severely damaged then loss of vision will occur which may not be reversible by treatment. 

The retinal changes when they first occur cause no apparent visual problems. Therefore all adults with diabetes should have regular eye checks.

This is impossible to say. Even diabetics who carefully control their diabetes may develop sight threatening changes but good control appears to reduce the risk. The risk of visual disturbances increases with the length of time the diseases has been present. 

In individuals where retinal changes are confirmed, treatment with a Laser as a hospital out-patient is effective in bringing the situation under control in most of the cases.

All patients who have received laser treatment need to continue to attend Eye Hospital clinic as laser therapy does not cure the basic problem. Months or even years later further treatment may be necessary. 

This treatment is normally painless and individuals receiving therapy can usually return to their own occupation the following day.
 

You may be one of the diabetics who develop sight threatening changes. By the time you yourself are aware of visual problems the disease could well have progressed to a stage where treatment is difficult or impossible.

A regular eye check every year for diabetics is never a waste of time and will give you the best chance of preserving your sight.