Methods: Patients with diabetic macular edema will be assigned to receive either micropulse 810nm diode laser photocoagulation or argon laser photocoagulation therapy. First, in a smaller clinical trial, patients will be assigned to single or double density micropulse 810nm diode laser to determine best strategy for this therapy. Visual acuity, fundus photographs and fluorescein angiography, and optical coherence tomography measurements , autofluorescence and mfERG were obtained at baseline and at 1, 3 and 6 months and 12 months.