Diabetic macular edema is the major cause of vision impairment in patients with non-proliferative diabetic retinopathy. Thickness and pathological alterations in each retina layer of diabetic macular edema (DME) patients can be performed by optical coherence tomography (OCT) device. And retinal light sensitivity at specific retinal point and fixation state can be detected by microperimetry qualitatively and quantitatively. Moreover, OCT can discover pathological anatomical changes in the retina of DME patients, thus facilitating the interpretation of the structure-function relationship in DME with combination of microperimetry results. At present, there are various therapies for DME patients, and the primary method in evaluating therapeutic efficacy is to compare the pathological changes in the retina before and after treatment by OCT. Besides, microperimetry can provide information in visual function restoration. The combined application of OCT and microperimetry has broad prospects in the diagnosis and treatment of DME patients.