 Obstructive sleep apnea syndrome OSAS is a common disease, with a prevalence evaluated between 5 - 7 in the general population. OSAS is characterized by recurrent episodes of partial or complete upper airway obstruction during sleep, which are nearly systematically associated with a desaturation-reoxygenation sequence, an admitted detrimental stimulus for the cardiovascular system. It has now been demonstrated that OSAS per se is able to generate hypertension, atherosclerosis and autonomic dysfunction high sympathic tone and increase in baseline heart rate, all conditions possibly interacting with ocular vascular regulation. OSAS has major consequences on the ocular level since it is associated with a higher frequency of optic neuropathies, such as glaucoma and nonarteritic ischemic optic neuropathy NAION, both with functional severe prognosis. Most of vascular changes associated with OSAS have been studied at the level of macrovasculature. In terms of physiopathology, the main effects on the vascular system in OSAS are sympathetic hyperactivity, oxidative stress, development of endothelial dysfunction, systemic inflammation and metabolic alterations such as the appearance of insulin resistance. All these mechanisms can affect the microcirculation of the eye, especially the optic nerve and choroid. Our hypothesis is that the eye microvasculature is affected by OSAS, and these lesions may be detected via a reduced autoregulation of blood flow in humans. 