Diabetic retinopathy (DR) is a complication of diabetes in which blood vessels supplying blood to the back of the eye (retina) are dysfunctional. This can lead to an improper supply of oxygen and nutrients to the retinal tissue, or it may trigger the formation of new blood vessels in response to the oxygen/nutrient deficiency. Ultimately affecting the normal vision. There is no known marker that will provide information on the health status of retinal blood vessels. Using highly specialized cells in the blood, this study will try to discover a marker of DR.