The hypothesis is that the pressure in the retinal veins increases under a short-term lack of oxygen and leads to a decreased blood circulation. On the basis of measurements in the hypobaric chamber this hypothesis should be verified.

Conduct a pilot study to describe and quantify the retinal venous pressure (RVP) in healthy volunteers under conditions of controlled, reduced ambient and oxygen partial pressure in the pressure chamber of the Aeromedical Institute FAI in Dübendorf, Switzerland. Obtaining evidence of the adaptation behavior of the retinal vascular system in controlled, short-term hypoxic changes.

Inclusion Criteria:

• healthy

Exclusion Criteria:

• eye diseases
• systemic diseases
• term medication (except contraceptives)
• pregnancy
• allergies to the ingredients Alcain, Tropicamide and Phenylephrine
• blood pressure levels except standard (<60 /> 140 mmHg)
• oxygen saturation (SO2) <90%

healthy volunteers