The goal of this clinical trial is to evaluate whether remote ischemic conditioning (RIC) is a safe and effective treatment for non-proliferative diabetic retinopathy (NPDR) in adults aged 40-80 years with type 2 diabetes. The study aims to address the limitations of current treatments for NPDR by using RIC, a technique involving repeated cycles of ischemia and hypoxia stimulation to activate protective mechanisms against retinal damage. The main questions it aims to answer are: Does RIC improve the Diabetic Retinopathy Severity Score (DRSS) after one year of treatment? Does RIC reduce the incidence of vision-threatening proliferative diabetic retinopathy (PDR)? What are the changes in retinal neurovascular unit parameters, visual acuity, and retinal oxygen saturation after RIC treatment? Participants will: Undergo RIC therapy using a specialized device on both upper limbs (or a placebo intervention for the control group) for 1 year. Complete 5 cycles of RIC or placebo treatment twice daily, 5 days per week. Receive routine care for diabetic retinopathy as per clinical guidelines. Key outcome measures: Primary outcome: Change in DRSS from baseline after one year. Secondary outcomes: Incidence of PDR, changes in visual acuity, retinal neurovascular unit measures, retinal oxygen saturation, and serum biomarkers (e.g., VEGF, CRP, IL-6). This randomized, double-blind, placebo-controlled trial aims to recruit 68 participants to ensure 60 complete the study, accounting for a 13% dropout rate. The findings are expected to provide insights into RIC as a novel intervention for NPDR, reducing blindness risk and supporting future large-scale trials.