Diabetes is first and foremost a disease that affects blood vessels all over the body, including the eye. The tiny blood vessels in the retina are often among the first to show changes – they can leak, they can dry up and disappear, and new ones can grow where they do not belong. Some of these changes are very mild and eyesight is unaltered. Others are much more severe and vision can be lost.
Good eyesight in diabetes is not an indication that there is no problem in the retinas. Many severe changes can develop to an advanced stage before they show themselves in reduced vision. All people with diabetes should have their eyes regularly monitored in some way (having photographs done or being examined by a doctor).
Treatment often works to save the eyesight but it works best when it is applied early in the disease. This again means that regular follow-up is important. As a rule every person with diabetes should be evaluated once a year as a minimum. When changes start to occur then the monitoring needs to be done more frequently.