Measurement of Ocular Blood Flow and Retinal Oxygen Extraction in Diabetic Patients

Inclusion Criteria: * Men and women aged ≥ 18 years * Signed informed consent * Previously diagnosed diabetes mellitus * Normal ophthalmic findings except diabetic retinopathy, unless the investigator considers an abnormality to be clinically irrelevant * Planned initiation of therapy with GLP-1 receptor agonist (Semaglutide, Ozempic®; Liraglutide, Victoza®) or GIP/GLP-1 receptor agonist (Tirzepatide, Mounjaro®) by a diabetes specialist Exclusion Criteria: * 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, except diabetes, as judged by the clinical investigator * Abuse of alcoholic beverages * Blood donation during the previous three weeks * Presence of any abnormalities preventing reliable measurements in the study eye as judged by the investigator * Previous laser photocoagulation treatment in the study eye * Best corrected visual acuity \< 0.4 Snellen * Women of childbearing potential (neither menopausal, nor hysterectomized, nor sterilized) not using effective contraception * Pregnancy, planned pregnancy or lactation