Intravitreal Triamcinolone Acetonide for Treatment of Refractory Diffuse Diabetic Macular Edema

Inclusion Criteria: * Diabetes mellitus (type 1 or 2) * Diabetic macular edema in study eye associated to diabetic retinopathy * Diffuse macular edema defined as macular thickening determined by biomicroscopy and fluorescein angiography. * Best corrected visual acuity between 34 (20/200) and 68 letters (20/50). * Macular thickness greater than 300 mcm on OCT. Exclusion Criteria: * Uncontrolled systemic disease * Start of medical therapy for diabetes or change in treatment from oral to insulin four months before initial visit. * HbA1c levels greater than 10% * Presence of retinal venous occlusion, cystoid macular edema,or other condition that would contribute to macular edema. * Presence of epiretinal membrane * Presence of vitreomacular traction in the study eye. * Aphakic or anterior chamber intraocular lens in the study eye. * Neovascularization of disc or elsewhere in the study eye. * History or presence of choroidal neovascularization in the study eye. * Presence of rubeosis irides in the study eye. * Eye opacity that interfere with clinical documentation and photography. * Intra-ocular surgery 90 days before initial visit. * Previous vitrectomy in study eye. * Previous history of intravitreal or periocular corticoid or any other intravitreal drug in study eye. * Scheduled surgery for study eye. * Patients with known allergies to fluorescein, iodo-povidone or any component of study drug.