Coupling of Neural Activity and Retinal Blood Flow in Diabetes

Inclusion Criteria:

• Men and women aged over 18 years, nonsmokers
• Normal findings in the medical history (except diabetes) and physical examination unless the investigator considers an abnormality to be clinically irrelevant
• normal laboratory findings (except diabetes associated parameters) unless the investigator considers the abnormality to be clinically irrelevant
• normal ophthalmic findings (except mild diabetic retinopathy), Ametropia less than 6 diopters
• inclusion criterion of patients is type I diabetes with non or mild non-proliferative retinopathy

Exclusion criteria

Any of the following will exclude a healthy subject from the study:

• Regular use of vasoactive drugs
• Abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Blood donation during the previous 3 weeks
• History or presence of any ocular pathology
• History or family history of epilepsy
• Systemic hypertension defined as systolic blood pressure >150mmHg, diastolic blood pressure >90mmHg
• Pregnancy

Any of the following will exclude a subject with diabetes from the study:

• Presence of non-insulin dependent diabetes, maturity onset diabetes of the young (MODY diabetes)
• History or presence of any other diabetes induced vascular pathologies or any other ocular condition other then diabetic retinopathy
• Best corrected visual acuity <0.8
• Previous laser photocoagulation treatment
• Systemic hypertension defined as systolic blood pressure >150mmHg, diastolic blood pressure >90mmHg
• History or family history of epilepsy
• Abuse of alcoholic beverages, participation in a clinical trial in the 3 weeks preceding the study
• Symptoms of a clinically relevant illness in the 3 weeks before the first study day
• Blood donation during the previous 3 weeks
• Pregnancy