Macular edema has various causes, the common ones are: 1, traction diabetic macular edema: by the presence of fibrovascular membrane near the macula, traction macula leads to macular edema and translocation, vision can be improved to varying degrees after surgical removal of the vascular membrane. 2, diabetic retinopathy macular edema: the incidence is low in eyes with posterior vitreous detachment, and it has been observed that some patients with spontaneous production of posterior vitreous detachment have improved visual acuity with reduced macular edema. The cross-linking of collagen is 3 times higher in eyes with diabetic retinopathy than in normal eyes, and the posterior vitreous cortex is thickened, and OCT shows that the macula is flattened and thickened by traction, which can be combined with edema. In some cases, the edema can be improved to some extent by vitrectomy combined with cortical vitreous removal. Some efficacy has been recently reported with both glucocorticoids (tretinoin) and anti-angiogenic drugs (Avastin, Lucentis and Macugen) injected into the vitreous cavity. This part of the treatment and research are accumulating. 3.Cystic macular edema: It is presumed that the reason why the macular area is prone to cystic edema is related to the thin boundary membrane within the macula, the tighter adhesion of vitreoretinal, and the direct anchoring of the vitreous into Müller cells. Vitrectomy surgery has been shown to be effective in lens-free and IOL eyes, with many studies reporting an average improvement in vision of more than 3 to 5 lines.