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

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

The prevalence of diabetes is increasing, with type 2 diabetes mellitus comprising over 90% of cases. Diabetes mellitus complications, including diabetic retinopathy (DR), impose significant health burdens. GLP-1 receptor agonists (GLP-1RAs) and dual GIP/GLP-1 receptor agonists show promise in improving cardiovascular and kidney outcomes, but their effects on retinal microvasculature and neuroprotection remain unclear. This study investigates the impact of GLP-1RAs (semaglutide, liraglutide) and GIP/GLP-1-dual agonists (tirzepatide) on ocular blood flow and retinal function in DM 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