Altered retrobulbar hemodynamics in patients who have transient monocular blindness without carotid stenosis.
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.
Chao
A-Ching
AC
Department of Neurology, Kaohsiung Medical University and Hospital, Kaohsiung, Taiwan.
Hsu
Hung-Yi
HY
Chung
Chih-Ping
CP
Chen
Yen-Yu
YY
Yen
May-Yung
MY
Wong
Weng-Jang
WJ
Hu
Han-Hwa
HH
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