Imaging of the parafoveal capillary network in diabetes.

The retinal vasculature is an extremely complex system that is adapted to support the metabolic demands of the retinal structures, but on the other hand maintain the optimal optical qualities of this tissue. Through histological studies and clinical studies using fluorescein angiography we have learned a lot about the retinal vasculature in its physiological state and in different diseases, but both of these study methods have serious limitations that limit their extensive application in healthy subjects or in patients with early disease. In this current review we will present early observations about the retinal vasculature from several novel noninvasive imaging modalities like adaptive optics SLO, retinal functional imager, adaptive optics OCT and Doppler OCT. Some of these instruments allow a more detailed in vivo examination of the retinal vasculature than fluorescein angiography without its potentially serious side effects, thus better allowing us to further study retinal vascular homeostasis in healthy subjects and to identify preclinical changes in early disease stages.