5. Blurry vision
An excess of sugar in the blood can damage the tiny blood vessels in the eyes, which can cause blurry vision.
This blurry vision can occur in one or both of the eyes and may come and go.
If a person with diabetes goes without treatment, the damage to these blood vessels can become more severe, and permanent vision loss may eventually occur.
6. Slow healing of cuts and wounds
High levels of sugar in the blood can damage the body’s nerves and blood vessels, which can impair blood circulation.
As a result, even small cuts and wounds may take weeks or months to heal. Slow wound healing also increases the risk of infection.