Study of Ocular Blood Flow in Patients With Glaucoma and/or Obstructive Sleep Apnea Syndrome (OSAS)

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.

This project aims to demonstrate, quantify, and analyze the vascular modifications of the eye associated with OSAS trough a comparative clinical study on glaucoma patients and OSAS patients and matched healthy subjects for the regulation of the eye blood flow using confocal laser Doppler flowmetry (LDF). The regulation of the ocular blood flow will be assessed using several stimuli and measured using a new confocal LDF.