Hi, There might be three reasons for blurry vision in your daughter 1) The description here is of classical short sightedness- she might need a correction glass in that case; advice an optometrist consultation first 2) Abnormal blood glucose levels can cause such symptoms - check for glucose control 3) Metformin can rarely be a cause. If the above two things are ruled out, Metformin may be pin pointed. Do not stop metformin yourself; alternatives like insulin or other oral medications has to be instituted before stopping metformin. Consult your physician for any change in medications. I hope the above information helps you. Thanks for writing into healthcaremagic.