Symptomatic and asymptomatic retinal embolism have different mechanisms.
OBJECTIVE
To investigate differences between symptomatic and asymptomatic retinal embolism regarding the frequency and source of cerebral microemboli.


METHODS
Thirty-seven patients with transient monocular blindness or retinal infarction and 27 patients (29 eyes) with asymptomatic retinal embolism were prospectively enrolled. Patients underwent a transcranial Doppler study and noninvasive imaging of the cervical internal carotid arteries (ICA). The middle cerebral artery (MCA) ipsilateral to the affected eye was monitored for 30 minutes for microembolic signals (MES), which were saved and analyzed offline. Age-matched controls (n=15) had no history of retinal or brain ischemia, <50% ICA stenosis, and normal ophthalmologic examinations.


RESULTS
MES were detected in 0/15 (0%) controls, 11/37 (30%) MCAs in the symptomatic group (P=0.02), and 3/29 (10%) MCAs in the asymptomatic group (P=0.54). Nine of 11 (82%) symptomatic eyes with MES had ipsilateral ICA stenosis of > or =50%, as compared with 0/3 (0%) eyes in the asymptomatic group with MES (P=0.03). Both MES and ICA stenosis of >50% were present in 9/37 (24%) cases in the symptomatic and in 0/29 (0%) cases of the asymptomatic group (P=0.0036).


CONCLUSIONS
The frequency and potential source of cerebral microemboli in symptomatic and asymptomatic retinal embolism are different. Cerebral microemboli are more frequent in symptomatic patients and are associated with ICA stenosis.
Wijman
Christine A C
CA
Department of Neurology, Stanford University Medical Center, Palo Alto, Calif 94304-1705, USA. cwijman@stanford.edu
Gomes
Joao A
JA
Winter
Michael R
MR
Koleini
Behrooz
B
Matjucha
Ippolit C A
IC
Pochay
Val E
VE
Babikian
Viken L
VL
D000368:Aged; D020757:Amaurosis Fugax / Q000000981:diagnostic imaging*; D002343:Carotid Artery, Internal / Q000000981:diagnostic imaging; D016893:Carotid Stenosis / Q000000981:diagnostic imaging; D015331:Cohort Studies; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000000981:diagnostic imaging*; D020766:Intracranial Embolism / Q000175:diagnosis / Q000000981:diagnostic imaging*; D008297:Male; D015356:Retinal Artery Occlusion / Q000000981:diagnostic imaging*; D017585:Ultrasonography, Doppler, Transcranial