The present study was performed in compliance with the Declaration of Helsinki and Good Clinical Practice (GCP) guidelines. The study protocol was approved by the Ethics Committee of the Medical University of Vienna. A total of 24 healthy male subjects aged between 19 and 35 years participated. The nature of the study was explained to all subjects, and they gave written consent to participate. Each subject passed a screening examination including 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 amino-transferase, aspartate transcarbamylase, γ-glutamyltransferase, alkaline phosphatase, total bilirubin, and total protein); hepatitis A, B, and C and HIV serology; urine analysis; and a urine drug-screening. Subjects were excluded if any abnormality was found as part of the pretreatment screening, unless the investigators considered the abnormality to be clinically irrelevant. Moreover, an ophthalmic examination, including slit lamp biomicroscopy and indirect funduscopy, was performed. Inclusion criteria were normal ophthalmic findings, ametropia of less than 3 D, and anisometropia of less than 1 D.