The accuracy of visible retinal emboli in the setting of acute retinal arterial obstruction as a"diagnostic test' for the detection of a hemodynamically significant carotid artery lesion

Purpose.To determine the likelihood of a hemodynamically significant carotid artery lesion in the setting of acute retinal arterial occlusion, given the presence of a visible retinal embolus. Methods. A retrospective crosssectional study was performed on patients with acute retinal arterial obstruction in two tertiary North American Eye centres to assess the accuracy of retinal emboh' as a "diagnostic test" for the detection of a hemodynamically significant carotid lesion (HSCAL), detected by carotid doppler ultrasonography. The study was designed to detect a positive likelihood ratio of 4. Results. The 71 patients, who met our study criteria, were divided into an embolie and non-embolic group, based on the presence of visible retinal emboli. 24 patients had visible retinal emboli, whereas, the remaining 47 did not. The prevalence of HSCAL was 18% (13/71). The sensitivity and specificity of visible retinal emboli for the detection of a HSCAL was 46% and 69%, respectively. The presence of a visible retinal embolus generated a likelihood ratio of 1.48; 95% CI (.437, 5.00). The absence of a visible retinal embolus generated a likelihood ratio of .783; 95% CI (.231, 2.65). Conclusions. The presence of visible emboli in the setting of acute retinal arterial obstruction is not accurate for the detection of a hemodynamically significant carotid lesion and, thus, this clinical sign should not be used to determine when to obtain carotid doppler ultrasonography in the setting of an acute retinal arterial obstruction.