The study protocol was approved by the Ethics Committee of Vienna University School of Medicine and followed the guidelines of Good Clinical Practice and the Declaration of Helsinki. Twelve healthy male nonsmoking subjects were included. Volunteers signed a written informed consent and passed a screening examination that included medical history and physical examination; 12-lead electrocardiogram; complete blood count; activated partial thromboplastin time; thrombin time; fibrinogen; clinical chemistry (sodium, potassium, creatinine, uric acid, glucose, cholesterol, triglycerides, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase, alkaline phosphatase, total bilirubin, and total protein); hepatitis-A, -B, -C and HIV-serology; and urinalysis. Subjects were excluded if any abnormality was found as part of the screening, unless the investigators considered an abnormality clinically irrelevant. An ophthalmic examination was performed in each subject before the study day. Inclusion criteria were normal ophthalmic findings, ametropia of less than 3 D, and anisometropia of less than 1 D. In all subjects, the right eye was studied.