The Effect of the Glycemic Variability on Macular Retinal Microcirculation and Cognitive Functions in Patient With Type 1 Diabetes

HbA1c doesn't explain all the microvascular complications of diabetes, especially microvascular complications. Glycemic variability is associated with increased oxidative stress, free radicals and endothelial dysfunction; it contributes to the pathogenesis of diabetic complications. The relationship between glycemic variability and microangiopathic complications especially retinal but also neurological, needs to be studied. The principal objective of Revadiab study is to demonstrate a correlation between glycemic variability and macular retinal microcirculation in patient with type 1 diabetes. The secondary objective is to search a correlation between glycemic variability and : * Alteration of cognitive functions. * Severity of peripheral diabetic retinopathy and retinal neuronal damage. * Other micro and macro angiopathic complications. * Oxidative stress and inflammation. Two groups of type 1 diabetic patients will be compared: * Case: Patient with significant glycemic variability. * Control: Patients without glycemic variability. The severity of diabetic retinopathy will be evaluated by the degree of occlusion of small vessels in the central retinal region as measured by OCT angiography. Acts or Product necessary to research : * Non-invasive retinal imaging (OCT and OCT- Angiography, retinophotography) * Neuropsychological tests. * Blood test.