Your retinas are nourished by a system of fine blood vessels. Diabetes can damage these blood vessels, causing them to leak or rupture. If the damage is severe, vision can be lost. Serious changes caused by diabetes often cause no symptoms until it is too late.
Keeping the eyes healthy boils down to two main factors: blood glucose and blood pressure. Tight management lowers the risk of developing retinopathy by 76% over the long term: <140/90 mmHg in adults and <90th percentile for age, sex, and height in children.
Go see your eye doctor right away if you have symptoms of retinal detachment, such as seeing a new floater or flashes of light, having what seems like a veil over your vision, or any other changes in vision.