Diabetic retinopathy (DR) is the eye complication of diabetes. It affects up to 80% of patients who have suffered diabetes for more than 20 years. DR is caused by abnormalities in retinal blood vessels. The retinal vessel changes are initially non-proliferative in nature (non-proliferative DR, NPDR). With NPDR, the leakages of micro-vessels form macular edema. The micro-vessels could also close off, causing macular ischemia. Both forms of lesions could lead to the partial loss of vision or blurry. NPDR could gradually progress to more severe proliferative DR (PDR) as new blood vessels form in retina, which is called neovascularization.  The newly formed vessels are usually fragile and often bleed into the vitroes. The bleeding could partially or completely block vision. Repeated disruption of retinal structure will lead to the scar formation and retinal detachment.

Most induced animal models of DR imitate only some features of DR, whereas spontaneous DR in NHPs recapitulates all the characteristics of human DR.

·  Spontaneous DR has been identified in the diabetic monkeys at KBI. Both macular edema and ischemia were detected using fundus photograph (FP), fluorescein angiography (FA) and optical coherence tomography (OCT).

·  Macular edema and ischemia can be also induced by laser at KBI and characterized using FP, FA and OCT.