Phase 2 Spectra Study to Evaluate the Safety and Efficacy of OPL-0401 in Patients With Diabetic Retinopathy

Inclusion Criteria * Adults ≥ 18 years; * Diabetes mellitus (type 1, type 2 or other forms); * Females who are not a woman of childbearing potential (WOCBP) or who agree to use contraception; * At least one eye with moderately severe to severe NPDR (DRSS levels 47 or 53) or mild PDR (DRSS level 61); * Patients with or without diabetic macular edema (DME) may be eligible if they meet protocol specified eligibility criteria; * Best corrected visual acuity (BCVA) early treatment of diabetes retinopathy study (ETDRS) letter score in the study at screening ≥69 letters (approximate Snellen equivalent of 20/40 or better) without CI-DME, or ≥75 letters when CI-DME is present (approximate Snellen equivalent 20/32 or better); * Anti-vascular endothelial growth factor (VEGF) or any laser treatment is not required nor anticipated in the study eye for least 6 months. Exclusion Criteria: * Body mass index ≥ 45 kg/m2 * Uncontrolled diabetes mellitus such as hemoglobin A1c (HbA1C) \> 11% or patients who are not currently treated for their diabetes; * Uncontrolled hypertension defined as systolic \> 160mmHg or diastolic \> 100 mmHg (despite hypertensive medication); * Proliferative Diabetes Retinopathy (PDR) with the exception of mild PDR (DRSS 61); * Evidence of retinal neovascularization (with the exception of mild PDR); * Any previous Diabetic Retinopathy treatment with focal or grid laser photocoagulation or Pan-Retinal Photocoagulation (PRP); * History of previously treated DME with fluocinolone acetonide implant (Iluvien®) injection; * Visual acuity loss due to an ocular condition that would not improve from treatment of DR or resolution of DME (i.e., foveal atrophy, pigment abnormalities, dense subfoveal hard exudates, nonretinal condition); * History of vitreoretinal surgery; * Intraocular surgery in the study eye within 3 months of randomization or anticipated over the course of the study; * Uncontrolled glaucoma (e.g. visual field loss or defined as (IOP) ≥ 25 mmHg despite treatment with anti-glaucoma medication); * Evidence of active infectious blepharitis, keratitis, scleritis, or conjunctivitis in either eye /any intraocular inflammation or infection in either eye within 3 months prior to randomization.