The present study conformed with the provisions of the Declaration of Helsinki and the Good Clinical Practice (GCP) guidelines. After approval of the study protocol by the Ethics Committee of the Vienna University School of Medicine and after written informed consent was obtained, 12 healthy nonsmoking male subjects were studied. All subjects were drug free for at least 3 weeks before inclusion and passed a prestudy screening during the 4 weeks before the first study day that included medical history and physical examination, 12-lead electrocardiogram, complete blood count, activated partial thromboplastin time, thrombin time, clinical chemistry (sodium, potassium, creatinine, alanine aminotransferase, γ-glutamyltransferase, total bilirubin, total protein), hepatitis (types A, B, and C) and HIV serology, urinanalysis, and an ophthalmic examination. Subjects were excluded if any abnormality was found as part of the pretreatment screening, unless the investigators considered an abnormality to be clinically irrelevant. In addition, subjects with ametropia of more than 3 D, anisometropia more than 1 D, or any evidence of eye disease that might interfere with the purpose of the present trial were excluded. During the week after completion of the study, a follow-up safety examination was scheduled for all participating subjects. This follow-up included physical examination, electrocardiogram, complete blood count, activated partial thromboplastin time, thrombin time, clinical chemistry (sodium, potassium, creatinine, alanine aminotransferase, γ-glutamyltransferase, total bilirubin, total protein), and urinanalysis.