Insulin treatment is crucial for glucose control. Many patients with type 2 diabetes exhibit inadequate glycemic control in spite of combination of oral antidiabetic drugs and eventually need insulin therapy. Patients who need insulin therapy are older and have poor visual acuity, which predispose to inaccurate dosing and consequent hyper or hypoglycemia.In this study, the investigators examined the clinical usefulness of a magnifier for elderly diabetic patients who had used insulin pens.