Hi, I had gone through your question and understand your concerns. circles and zizgzag line in the vision are due to fluid are blood leakage in layers of eye. .These are called as floaters. In diabetics it is most commonly due to diabetic retinopathy. In this condition blood vessels in the retina will be coated with fat layer that leads to decreased blood supply and leads to extra connections forms,and leakage of blood occurs.Those things visiable as circles and zigzag lines. Other possibility is vitreous hemorrhage due to diabetis. Treatment will be... -Strict control of your blood sugar levels. -Switch to insulin injection according to the blood gluvose levels. -Consult ophtholmologist and get a RETINOSCOPY, which clearly indicates the cause of your problem. Early stages of cataract also may cause this type of problem but it associates with blurring of vision. Hope this will help you. Thank you