The difficulty to measure blood flow in humans is connected with the necessity of using not invasive, reliable and reproducible techniques.

There is several quantitative approaches to study eye blood flow which do not answer all these specifications. The laser doppler velocimetry allows movement speed measures but not vessel diameter. Optical coherence tomography doppler allows a simultaneous diameter and speed of travel (movement) measures, but presents a limited spatial resolution and thereby not easily reproducible vessel diameter measures.

The investigators propose development of a technique allowing a simultaneous diameter and velocity measure of these vessels.

The eye blood flow plays a fundamental role in the eye physiology, insuring the metabolic contributions of various eye tissues, in particular those associated with the vision photochemical processes. Eye blood flow changes are involved in the physiopathology of several frequent eye diseases susceptible to lead to blindness (glaucoma,age-related macular degeneration, venous or arterial occlusions). Numerous systematic pathologies can also alter eye blood flow (diabetes, sleep apnea, arterial high blood pressure, inflammation).

The difficulty to measure blood flow in humans is connected with the necessity of using not invasive, reliable and reproducible techniques.

There is several quantitative approaches to study eye blood flow which do not answer all these specifications. The laser doppler velocimetry allows movement speed measures but not vessel diameter. Optical coherence tomography doppler allows a simultaneous diameter and speed of travel (movement) measures, but presents a limited spatial resolution and thereby not easily reproducible vessel diameter measures.

The investigators propose development of a technique allowing a simultaneous diameter and velocity measure of these vessels.

Inclusion Criteria:

• Willing and able to give written Informed Consent and to comply with the requirements of the study protocol
• Person affiliated to social security
• Age between 18 and 80 years
• Capable of focusing a target without ocular micro stuttering
• For healthy subject : absence of ocular and systemic pathology and no medical treatment
• For subject with glaucoma : Primitive open-angle glaucoma unilateral or bilateral. Visual field must be considerate as compatible and reliable with campimetric impairment known in glaucoma.
• For subject wih retinal veinous occlusion : Retinal central vein occlusion or branch retinal vein occlusion medically confirmed with an eye fundus exam and fluorescein angiography.

Non-inclusion Criteria:

• Subject mentioned in L1121-5 to L1121-8 article of French Health Code : pregnant women, women capable of child bearing without contraceptive measures, under-age subject, subject under juridic protection or not able to give informed consent, subject deprived of liberty
• Any systemic medication with action on intraocular pressure such as sympathomimetic and beta blocker
• Hypersensitivity to tropicamide or its derivatives or to any eye drops excipients
• Subject who do not want to take part to the study
• Subject participating to another clinical trial
• Subject who can't come back for follow up visits
• Subject with lenses and who can't stop wearing them for the study protocol
• Close or narrow anterior chamber angle
• For healthy subject : Ametropia > 3 diopter, subject with non evolutive or evolutive ocular pathology
• For subject with glaucoma : Ametropia > 3 diopter, secondary glaucoma, closed angle glaucoma, isolated intraocular hypertonia, eye surgery within 3 months before the beginning of the study, trabeculoplasty, filtration surgery, associated evolutive or non-evolutive ocular pathology
• For subject with retinal veinous occlusion : Ametropia > 3, associated evolutive or non-evolutive ocular pathology, patient already treated with intravitreal injection with anti-VEGF or dexamethasone implant (no older than 4 months)