Dual beam Doppler Fourier-domain Optical coherence tomography (DOCT) is a noninvasive technique to quantify total retinal blood flow.

To enable further development of this technique it is essential to assess short- and long-term reproducibility of DOCT blood flow measurements.

In the present study, total retinal blood flow will be measured with DOCT at multiple time points to gain information of short- and long-term reproducibility. In addition, provocation with flickering light will be performed, which is known to lead to vasodilatation and an increase in retinal blood flow in healthy subjects. Vessel diameters will also be measured using the Dynamic Vessel Analyzer (DVA).

Inclusion Criteria:

• Men and women aged between 18 and 35 years
• Non-smokers
• Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant
• Normal ophthalmic findings, ametropy < 3 Dpt.

Exclusion Criteria:

• Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
• Treatment in the previous 3 weeks with any drug (except contraceptives)
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Blood donation during the previous 3 weeks
• Pregnancy, planned pregnancy or lactating
• History or family history of epilepsia