Yes, the diabetes can cause double vision because of the unstable eyes pressure. In addition, you may get the blurry vision if you get the diabetes. You'd better protect the eyes through the good rest and good diet. You could eat more food with vitamin C to improve the vision. You could also use some eyes drops to release your eyes to make them feel comfortable.
It's true that diabetes can cause double vision. It's because the diabetes may affect some nerves of your eyes. Those nerves are controlling your eye movement, once they are affected by diabetes, your two eyes may not work coordinately, so you will have double vision. Diabetes often comes with high blood pressure. High blood pressure may do damage the blood vessels in your eyes, thus you also may get double vision.
There are some obvious symptoms of diabetes. For example, go to the bathroom frequently, always feeling thirst, and losing weight without trying.
I advise you to keep on a diet, keeping it in balance will be helpful for your cure. Hope you well soon!