Diabetes mellitus is an abnormal condition that occurs because of constantly increasing glucose levels in the blood. It results in Diabetic Retinopathy (DR), a hazardous eye condition where quick changes in blood sugar damage the vascular region of the retina. If timely treatment is not received, this condition can result in blindness and visual loss. Optical Coherence Tomography Angiography (OCTA) has rapidly become an indispensable part of the state of the art in modern ophthalmic diagnostic tools, particularly for DR, by providing detailed, high-resolution views of the retinal microvasculature. The significance of the technology is that it further emphasizes advances in imaging techniques that can better reveal alterations in micro vessels, improving accuracy in the diagnosis and monitoring of disease. The proposed review focuses on current 3D OCTA methods and tools to emphasize vessel segmentation, reconstruction, and visualization innovation for an intensive retinal examination. Above all, the key technologies are dominated by deep learning algorithms and more advanced 3D modelling frameworks that enable depth-resolved imaging, therefore further understanding DR progression for potential early interventions. The review covers the challenges and potential of newer techniques, such as 3D modeling, automated shape analysis and hemodynamic analysis, toward optimizing OCTA’s power to distinguish between disease stages. The review concludes with some further research directions on enhancing the reliability of the diagnostic approach, applying standardized data to broader clinical use, and exploring more uses of 3D OCTA in retinal disease management.