Effect of carotid endarterectomy on retinal function in asymptomatic patients with hemodynamically significant carotid artery stenosis

INTRODUCTION    The corrective effect of carotid endarterectomy (CEA) on impaired ophthalmic artery flow in patients with significant internal carotid artery (ICA) stenosis presenting with ocular ischemic syndrome (ie, symptomatic patients) is well established. However, there is no clear evidence regarding the efficacy of CEA for improvement of neuroretinal function in patients without symptoms of ocular ischemic syndrome.
OBJECTIVES    We aimed to determine the effects of CEA on retinal function in asymptomatic patients with hemodynamically significant ICA stenosis.
PATIENTS AND METHODS    We enrolled 46 patients with ICA stenosis referred for CEA. Full-field electroretinogram (ERG), pattern ERG, and pattern visual evoked potentials, as well as optical coherence tomography and ophthalmologic examination of both eyes were performed 1 day before and 3 months after CEA. We analyzed eyes ipsilateral (EIE) and contralateral (ECE) to CEA.
RESULTS    We observed an increase in several ERG wave parameters in both eye groups, compared with baseline values: rod b-wave amplitudes (P <0.00001 for EIE and P = 0.0001 for ECE); rod-cone a-wave (P = 0.02 for EIE) and b-wave (P = 0.001 for EIE and P = 0.01 for ECE) amplitudes; cone single flash a-wave (P = 0.05 for EIE and P = 0.004 for ECE) and b-wave (P <0.0001 for EIE and P <0.0001 for ECE) amplitudes; cone 30-Hz flicker amplitudes (P = 0.0003 for EIE and P <0.0001 for ECE); and oscillatory potential wave index amplitudes (P <0.00001 for EIE).
CONCLUSIONS    The amplitudes of the standard full-field ERG were significantly increased following CEA in EIE and, to a lesser extent, in ECE. Multimodality ERG may represent a unique tool for investigating the effects of carotid revascularization on neuroretinal function in asymptomatic patients with ICA stenosis.