The inclusion criteria were age ≥ 18 years and a diagnosis of DME involving the central macula in patients with type 1 or 2 diabetes mellitus. The central macular thickness (CMT) had to be ≥250 μm in the central subfield based on the Heidelberg Spectralis-OCT (Heidelberg Engineering, Heidelberg, Germany) images. Participants were required to have a best-corrected visual acuity (BCVA) of 0.097 to 1.0 logMAR units, hemoglobin A1c (HbA1C) ≤ 12%, and reduced vision attributable to foveal thickening from DME without any other causes. In addition, women of childbearing age were included only if they were willing not to become pregnant and to use a reliable form of birth control during the study period.
The exclusion criteria were history of vitreoretinal surgery, panretinal or macular laser photocoagulation, use of intraocular or periocular corticosteroids or anti-VEGF drugs within 6 months of the screening, vision reduction due to causes other than DME, regressed and currently inactive proliferative DR, ocular inflammation, cataract or other intraocular surgery within 6 months of the screening, laser capsulotomy within 3 months of the screening, aphakia, refractive error (spherical equivalent) greater than −6 diopters (D), or any disease that would compromise the visual acuity, or require medical or surgical intervention during the study period. In addition, patients were excluded if they had active iris neovascularization, vitreous hemorrhage, tractional retinal detachment, preretinal fibrosis involving the macula, visually significant vitreomacular traction or epiretinal membrane evident biomicroscopically or on OCT, structural damage to the center of the macula that would likely preclude improvement in the BCVA acuity after the resolution of macular edema, uncontrolled glaucoma or prior filtration surgery, or infectious blepharitis, keratitis, scleritis, or conjunctivitis. In addition, subjects were excluded if they had any of the following systemic conditions: uncontrolled diabetes mellitus, uncontrolled hypertension, history of cerebral vascular accident or myocardial infarction within 6 months, renal failure requiring dialysis or renal transplant, pregnancy or lactation, history of allergy to fluorescein or povidone iodine, only one functional eye, or an ocular condition in the fellow eye with a poorer prognosis than the study eye.