Thiazolidinediones (TZDs) are insulin sensitizers that decrease plasma glucose in type 2 diabetic patients. Thiazolidinediones can cause fluid retention and peripheral edema in diabetic patients, and the systematic fluid retention can be manifested as diabetic macular edema (DME). The overall goal of this study is to examine the effects of thiazolidinediones on the diabetic retinopathy and nephropathy.