The eye has long been recognized as a window to pathological processes occurring in the brain. By imaging the vascular system of the retina scientific understanding and clinical practice have been improved for a wide range of pathologies from diabetes to stroke and dementia.

Adaptive optics (AO) reveals retinal details that remain invisible with other current imaging techniques. Indeed, vessels can be perfectly visualized, making it possible to detect wall irregularities, accurately measure their different structures and monitor their evolution under treatment if necessary.

In AO, studies on retinal vessels involve the calculation of wall thickness (WT), outer diameter (OD), inner diameter (ID), wall cross-sectional area (WCSA) and wall to lumen ratio (WLR). An increase in WLR \> 0.31 is characteristic of hypertensive microangiopathy and predictive of cardiovascular and brain damage. This accurate assessment of microvascular structure may even be required in the near future in all patients with arterial hypertension. For vessels \> 300 microns in diameter, the increase in vessel wall thickness occurs without changing the ID, a process known as external hypertrophic remodeling. For small arteries \< 300 microns, remodeling occurs differently. The total volume of the vessel wall remains constant, but the OD and ID each decrease, a process known as inward eutrophic remodeling.

The objective of this study is to describe the parameters measured in AO in patients in the acute phase of a stroke and then at 3 months.