Visual electrophysiology in carotid endarterectomy: a systematic review
Sofia Pacheco-Moreira1, João Rocha-Neves2,3,4, Ana Marta5,6
1Faculty of Medicine, University of Porto, Al. Prof. Hernâni Monteiro, 4200-319, Porto, Portugal. aspmoreira@gmail.com.
Background:
To systematically evaluate changes in ocular electrophysiological function following carotid endarterectomy (CEA) and to determine whether electroretinography (ERG) and visual evoked potentials (VEP) can detect postoperative functional recovery of the retina and visual pathways.
Methods:
A systematic search of MEDLINE, Scopus, and Web of Science was conducted from inception to August 2025. Observational studies assessing electrophysiological outcomes (ERG, VEP, multifocal recordings, or electrooculography [EOG]) before and after CEA in adults with carotid stenosis were included. Study quality was evaluated using the NHLBI Study Quality Assessment Tools. Due to substantial clinical and methodological heterogeneity, a quantitative synthesis was not performed.
Results:
Four prospective observational studies were included, involving 95 patients with predominantly severe carotid stenosis (≥ 70%), with one cohort applying a ≥ 60% threshold. Electrophysiological findings were heterogeneous: VEP parameters generally showed no consistent postoperative improvement, whereas ERG demonstrated significant enhancement of oscillatory potentials and a-/b-waves amplitudes in 3 of the 4 included studies. Visual field indices improved in several cohorts, while structural parameters, particularly retinal nerve fiber layer thickness, remained stable. Changes in intraocular pressure were inconsistently reported. Overall methodological quality indicated a moderate-to-high risk of bias, primarily due to small sample sizes, lack of adjustment for confounders, and variability in electrophysiological protocols.
Conclusion:
The available evidence, while preliminary and exploratory, suggests a possible association between CEA and postoperative changes in electrophysiological parameters, most notably ERG-derived measures. These findings should be interpreted with considerable caution given the small number of studies, limited sample sizes, and substantial methodological heterogeneity. Whether ocular electrophysiology holds clinical utility in the perioperative assessment of carotid disease remains to be established by larger, adequately powered, and standardized prospective studies.