Diabetes is diagnosed when fasting blood glucose levels are over 125. If fasting blood glucose levels are allowed to be over 250 or even 200, diabetes is very poorly controlled.
Diabetes can cause more complications in your body. It is important to monitor your health and get treatment instantly. If you have diabetes, it is not impossible that you develop retinal detachments. That is why diabetic people are required to have their eyes (retinas) checked regularly to prevent this condition.
pre diabetes IS diabetes the difference is a line drawn in the sand, the only difference between pre diabetes and diabetes the ease of controlling the BG. it used to be that the definition of diabetes was BG over 250, they have moved that down to 200 and there is talk of moving it even lower.