Twenty patients with type 1 diabetes without diabetic retinopathy and without arterial hypertension will be compared with 20 sex and aged-matched healthy control subjects. To assess the presence of retinal endothelial dysfunction, the variations of the diameters of the retinal vessels will be assessed using the Dynamic Vessel Analyzer, before and after flicker light stimulation, sublingual nitroglycerin, neosynephrine eyedrops, and isometric contraction. To assess the presence of peripheral endothelial dysfunction, the microcirculation of the forearm skin will be studied using iontophoresis with acetylcholine delivery, and heat delivery, both coupled with blood flow measurement using laser Doppler. An intravital capillaroscopy of the phalanx skin will be performed. The serum levels of CRP, ICAM-1, VCAM-1, VEGF, angiopoietin 2 and endostatin will also be measured.