Non-invasive Measurement of Retinal Blood Flow Based on Vessel Analysis and Fourier Domain Optical Coherence Tomography in Patients With Hypertensive Retinopathy

Inclusion Criteria: Inclusion criteria for healthy subjects * Men and women aged over 18 years * Non-smokers * Normal findings in the medical history unless the investigator considers an abnormality to be clinically irrelevant * Systolic Blood Pressure ≤ 120 mmHg and Diastolic Blood Pressure ≤ 80 mmHg * Normal ophthalmic findings, ametropia \< 6 Dpt. Inclusion criteria for patients with hypertensive retinopathy * Men and women aged over 18 years * Hypertensive retinopathy stage 2 or 3 * Normal ophthalmic findings except hypertensive retinopathy stage 2 and 3, ametropia \< 6 Dpt. Exclusion Criteria: Any of the following will exclude a healthy subject from the study: * Symptoms of a clinically relevant illness in the 3 weeks before the first study day * Presence or history of a severe medical condition as judged by the clinical investigator * Presence or history of arterial hypertension * Regular use of medication, abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study (except oral contraceptive) * Blood donation during the previous three weeks * Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator * Ametropia \>= 6 Dpt * Pregnancy, planned pregnancy or lactating Any of the following will exclude a patient with hypertensive retinopathy from the study: * Participation in a clinical trial in the 3 weeks preceding the screening visit * Symptoms of a clinically relevant illness in the 3 weeks before the first study day * Presence or history of a severe medical condition as judged by the clinical investigator * Blood donation during the previous three weeks * Hypertensive retinopathy stage 4 * Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator * Ametropia \>= 6 Dpt * Pregnancy, planned pregnancy or lactating