Answer:
A person with diabetes should have an eye exam once per year. The exam should include dilating the eyes and having a slit lamp exam. The doctor will look for changes on the retina that come from diabetes damage (retinopathy). Retinopathy leads to blindness if it does not get treated. With treatment, vision can be protected.
If blood sugar is much higher or much lower than usual, vision may be blurred for a short time. The lens in the eye temporarily swells or shrinks after there are large changes in sugar levels. For this reason, it may not be ideal to schedule an eye visit to get glasses right after a diabetes medicine is adjusted to improve glucose control.