title: Altered retrobulbar hemodynamics in patients who have transient monocular blindness without carotid stenosis.
abstract: OBJECTIVE
  This study was to evaluate the retrobulbar hemodynamics in patients who have transient monocular blindness (TMB) without carotid stenosis.
  
  
  METHODS
  Fifty-nine patients who have TMB without carotid stenosis were studied along with 59 age- and sex-matched controls. Color Doppler-imaging was used to study the retrobulbar hemodynamic by measuring the flow velocities (peak-systolic velocity, and end-diastolic velocity), vascular resistance indices (pulsatility index, and resistance index) in central retinal arteries, short posterior ciliary arteries, and ophthalmic arteries. The patients were divided into 2 groups according to the attack frequency: group 1 (occasional TMB, 2 or fewer attacks, 26 patients) and group 2 (frequent TMB, 3 or more attacks, 33 patients).
  
  
  RESULTS
  The risk factors for atherosclerosis were similar between the cases and controls. The means of end-diastolic velocity were significantly lower in central retinal arteries and ophthalmic arteries, and the pulsatility index and resistance index were significantly higher in all the 3 retrobulbar vessels in TMB patients than for the controls. The differences between patients and controls were greater for the group-2 patients.
  
  
  CONCLUSIONS
  Patients who have TMB without carotid stenosis had altered retrobulbar hemodynamics with a generalized increase in vascular resistance in the retrobulbar arteries. The role of venous hypertension as an etiology needs further study.
authors.affiliation: Department of Neurology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan.
authors.forename: A-Ching
authors.initials: AC
authors.lastname: Chao
authors.forename: Hung-Yi
authors.initials: HY
authors.lastname: Hsu
authors.forename: Chih-Ping
authors.initials: CP
authors.lastname: Chung
authors.forename: Yen-Yu
authors.initials: YY
authors.lastname: Chen
authors.forename: May-Yung
authors.initials: MY
authors.lastname: Yen
authors.forename: Weng-Jang
authors.initials: WJ
authors.lastname: Wong
authors.forename: Han-Hwa
authors.initials: HH
authors.lastname: Hu
mesh_terms: D000368:Aged; D020757:Amaurosis Fugax / Q000209:etiology* / Q000503:physiopathology*; D016893:Carotid Stenosis; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000150:complications / Q000503:physiopathology; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D002537:Intracranial Arteriosclerosis / Q000150:complications / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009880:Ophthalmic Artery / Q000473:pathology / Q000503:physiopathology*; D011446:Prospective Studies; D012160:Retina / Q000503:physiopathology; D012161:Retinal Artery / Q000473:pathology / Q000503:physiopathology*; D012169:Retinal Vein / Q000503:physiopathology; D014655:Vascular Resistance