Diabetes retinopathy (DR) is the main cause of visual impairment in the working population worldwide. Patients with pre-diabetes and pre-clinic diabetic retinopathy are regarded as in high risk group of DR. The changes in morphology and function of renal neurons and retinal micro-vessels can be found in these patients at this stage. The changes of retinal nerve structure can be partly reflected by changes in the thickness of retina and nerve fiber layer. The changes in function of retinal neurons can be reflected by changes in color vision, contrast sensitivity, visual field and visual electrophysiology.With the development of optical coherence tomography angiography, changes in retinal micro-vessels can be observed prior to clinical detection of DR. In addition, many biomarker can also predict and evaluate DR. Since there is no way to prevent the occurrence and progress of DR at present, more attention should be paid in DR by observing the changes inthe retina mentioned above timely, to reduce its incidence and minimize the visual damage caused by DR.