there are multiple potential causes for blurry vision and speaking with your opthalomologist sooner rather than later makes sense. blurry vision due to high blood sugar levels is usually when glucose levels are very high such as well over 300 mg/dl. i would not expect the recent medication change to be an obvious culprit. in any case i'm confident your health care team can help you find the answers.
can lowering the dosage for an oral medication for diabetes such as glipizide cause my vision to be extremely blurry?