Revadiab is case-control study aimed to demonstrate that retinal capillary density is altered in patients with type 1 diabetes with glycemic variability compared to those with comparable glycemic control without glycemic variability. An OCT angiography will be used to precisely evaluate retinal capillary density.

A secondary objective will be to evaluate if glycemic variability is associated with cognitive dysfunction, using a neuro psychologic evaluation.

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.

Inclusion Criteria:

• Patients ≥ 18 years
• Type 1 diabetes (T1D)
• Using Free FreeStyle
• Diabete evolving for 10 years or more
• Case: Patients with glycemic variability, defined by a coefficient of variation (CV) > 36%, calculated from continuous glucose measurements data by Free Style Libre® (Abbott)
• Controls: Patients without glycemic variability, defined by a coefficient of variation (CV) ≤ 36%, calculated from Free Style Libre® data and matched to patients in the Case group for HbA1c (+/- 0.5%)

Exclusion Criteria:

• Type 2 diabetic patient
• Corticotherapy
• Comorbidity like cancer
• Antecedent of vitreoretinal pathology
• Antecedent of vitreoretinal surgery
• Important cataract, with an important opacity that prevents a reliable evaluation of capillary density in OCT angio
• Pregnant or lactating woman

Inclusion of adult patients with T1D with more than 10 years of diabetes and users of the FreeStyle Free continuous measurement system.

Case: Patients with glycemic variability, defined by a coefficient of variation (CV) > 36%, calculated from continuous glucose measurements data by Free Style Libre® (Abbott).

Controls: Patients without glycemic variability, defined by a coefficient of variation (CV) ≤ 36%, calculated from Free Style Libre® data and matched to patients in the Case group for HbA1c (+/- 0.5%).