Inclusion Criteria:  Part A  Panretinal photocoagulation-treated diabetic retinopathy (DR) patients with either no or inactive retinal neovascularization per investigator judgement in the study eye Male or female subjects of age ≥ 18 years Evidence of diabetic macular ischemia (DMI) per investigator´s judgement, defined as any degree of disruption of retinal vascularity in optical coherent tomography angiography (OCTA) Glycosylated Hemoglobin, Type A1C (HbA1c) of ≤ 12.0% Best-corrected visual acuity (VA) ≤75 letters (20/32) in the study eye Best corrected visual acuity (VA) in the non-study eye must be equal to or better than best corrected VA in the study eye. If both eyes are eligible and have identical best corrected VA the investigator may select the study eye. Women of childbearing potential (WOCBP) and men able to father a child must be ready and able to use two methods of contraception with at least one of them being a highly effective method of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly. Signed and dated written informed consent in accordance with International Council for Harmonisation-Good Clinical Practice (ICH-GCP) and local legislation prior to admission to the trial  Part B:  Panretinal photocoagulation-treated diabetic retinopathy (DR) patients with either no or inactive retinal neovascularization per investigator judgement Male or female subjects of age ≥ 18 years Presence of significant diabetic macular ischemia (DMI): Large foveal avascular zone (FAZ) defined as those with ≥0.5mm2 area present on optical coherent tomography angiography (OCTA). If FAZ is <0.5mm2 then an enlarged peri-foveal inter-capillary space in at least 1 quadrant will be sufficient. Glycosylated Hemoglobin, Type A1C (HbA1c) of ≤ 12.0% Best-corrected visual acuity (VA) ≤85 letters (20/20) in the study eye If both eyes are eligible, the investigator may select either eye to be the study eye. Women of childbearing potential (WOCBP) and men able to father a child must be ready and able to use two methods of contraception with at least one of them being a highly effective method of birth control per ICH M3 (R2) that result in a low failure rate of less than 1% per year when used consistently and correctly. Signed and dated written informed consent in accordance with International Council for Harmonisation-Good Clinical Practice (ICH-GCP) and local legislation prior to admission to the trial  Exclusion Criteria:  Part A:  Subjects receiving intravitreal (IVT) injections for active Diabetic Macular Edema (DME) (anti-vascular endothelial growth factor (VEGF), steroids) and macular laser in the previous 3 months to screening in the study eye Subjects receiving anti-VEGF IVT injections for active diabetic retinopathy (DR) in the previous 3 months to screening in the study eye Current or planned use of medications known to be toxic to the retina, lens or optic nerve (e.g. desferoxamine, chloroquine/hydrochloroquine, chlorpromazine, phenothiazines, tamoxifen, nicotinic acid, and ethambutol) Additional progressive eye disease in the study eye that could compromise best corrected visual acuity (VA) (best corrected visual acuity (BCVA)), uncontrolled glaucoma (intra-ocular pressure (IOP)>24), history of high myopia > 8 diopters in the study eye. Anterior segment and vitreous abnormalities in the study eye that would preclude adequate observation with spectral domain optical coherence tomography (SD-OCT) and optical coherent tomography angiography (OCTA). Any intraocular surgery in the study eye within 3 months prior to screening Glaucoma tube shunts Aphakia or total absence of the posterior capsule. Yttrium aluminum garnet (YAG) laser capsulotomy permitted, if completed more than 3 months prior to screening, in the study eye Subjects not expected to comply with the protocol requirements or not expected to complete the trial as scheduled (e.g. chronic alcohol or drug abuse or any other condition that, in the investigator´s opinion, makes the subject an unreliable trial subject) Further exclusion criteria apply  Part B:  Diabetic Macular Edema (DME), defined as a Central Subfield Thickness (CST) ≥ 305μm for men and ≥ 290 μm for women (Optovue Angiovue) in the study eye Subjects receiving intravitreal (IVT) injections for active DME (anti-vascular endothelial growth factor (VEGF), steroids) and macular laser in the previous 3 months to screening in the study eye Subjects receiving anti-VEGF intravitreal IVT injections for active Diabetic Retinopathy (DR) in the previous 3 months to screening in the study eye Heavily lasered macula in the study eye per investigator judgement History of vitrectomy in the study eye Epiretinal membrane with extended foveal contour distortion in the study eye Clinically significant disorganisation of retinal inner layer (DRIL) in the study eye Current or planned use of medications known to be toxic to the retina, lens or optic nerve (e.g. desferoxamine, chloroquine/hydrochloroquine, chlorpromazine, phenothiazines, tamoxifen, nicotinic acid, and ethambutol) Further exclusion criteria apply