In diabetes, there’s not only a change in the proportion of liquids in the blood. The liquid balance is altered throughout the body, and one of the most commonly affected organs is the eye. Inside the eye, the lens is a particular structure that helps us focus the images we see. But in early diabetes, the alteration of glucose in the blood would cause the lens to absorb extra fluid and swell. By changing the structure of the lens, diabetes would cause blurry vision and other problems.
People with advanced diabetes would also experience visual problems in the long term. However, these are the result of extensive damage to the nerves and the micro-circulation. This is called diabetic retinopathy, and it causes a wide range of visual problems depending on the patient and his condition.