Visual Outcome of Carotid Endarterectomy in Patients with Carotid Artery Stenosis

BackgroundCarotid endarterectomy (CEA) is deemed to restore the blood flow of the carotid and ophthalmic arteries in patients with carotid artery stenosis. However, specific changes in visual function before and after CEA are not well understood; hence, this observational study aimed to investigate the functional and structural changes in vision after CEA in those patients.MethodsPatients with severe carotid artery stenosis (>70% with standard carotid duplex scanning or arteriography) scheduled to undergo CEA were consecutively recruited for the study between September 2015 and July 2016. All patients underwent a standardized ophthalmic examination, including intraocular pressure (IOP) measurement, slit-lamp examination, and fundus examination. Visual acuity, best corrected visual acuity (BCVA), and kinetic and static visual fields (VFs) were tested to evaluate subjective visual function. Flash and pattern visual evoked potentials (VEPs) and an electroretinogram (ERG) were measured for objective visual function. Retinal nerve fiber layer (RNFL) thickness was scanned using optical coherence tomography for structural evaluation.ResultsThe study involved 15 patients (11 male and 4 female, corresponding to 30 eyes; mean age 62.8 ± 5.0 years). After CEA, both uncorrected visual acuity and BCVA improved, and IOP significantly decreased from 17.41 ± 2.59 to 15.95 ± 2.50 mm Hg (P = 0.0022). Kinetic VF range increased significantly (P = 0.0126) as did mean sensitivity from 18.8 ± 5.5 to 20.6 ± 4.3 dB (P = 0.0208), whereas mean defect decreased from 8.2 ± 5.3 to 6.5 ± 4.2 dB (P = 0.025). RNFL thickness was not significantly altered. Latency of the P2 wave on flash VEP reduced significantly after CEA (P = 0.0151), whereas the oscillatory potential amplitude of waveform 3 in the ERG significantly increased after CEA.ConclusionsOur results demonstrate that an improvement in carotid artery and ophthalmic artery blood flow after CEA does indeed enhance subjective and objective assessments of visual function in patients with carotid artery stenosis, including visual acuity, kinetic and static VF, P2 latency, and ocular pressure amplitude; however, it did not affect RNFL thickness. Carotid endarterectomy (CEA) is deemed to restore the blood flow of the carotid and ophthalmic arteries in patients with carotid artery stenosis. However, specific changes in visual function before and after CEA are not well understood; hence, this observational study aimed to investigate the functional and structural changes in vision after CEA in those patients. Patients with severe carotid artery stenosis (>70% with standard carotid duplex scanning or arteriography) scheduled to undergo CEA were consecutively recruited for the study between September 2015 and July 2016. All patients underwent a standardized ophthalmic examination, including intraocular pressure (IOP) measurement, slit-lamp examination, and fundus examination. Visual acuity, best corrected visual acuity (BCVA), and kinetic and static visual fields (VFs) were tested to evaluate subjective visual function. Flash and pattern visual evoked potentials (VEPs) and an electroretinogram (ERG) were measured for objective visual function. Retinal nerve fiber layer (RNFL) thickness was scanned using optical coherence tomography for structural evaluation. The study involved 15 patients (11 male and 4 female, corresponding to 30 eyes; mean age 62.8 ± 5.0 years). After CEA, both uncorrected visual acuity and BCVA improved, and IOP significantly decreased from 17.41 ± 2.59 to 15.95 ± 2.50 mm Hg (P = 0.0022). Kinetic VF range increased significantly (P = 0.0126) as did mean sensitivity from 18.8 ± 5.5 to 20.6 ± 4.3 dB (P = 0.0208), whereas mean defect decreased from 8.2 ± 5.3 to 6.5 ± 4.2 dB (P = 0.025). RNFL thickness was not significantly altered. Latency of the P2 wave on flash VEP reduced significantly after CEA (P = 0.0151), whereas the oscillatory potential amplitude of waveform 3 in the ERG significantly increased after CEA. Our results demonstrate that an improvement in carotid artery and ophthalmic artery blood flow after CEA does indeed enhance subjective and objective assessments of visual function in patients with carotid artery stenosis, including visual acuity, kinetic and static VF, P2 latency, and ocular pressure amplitude; however, it did not affect RNFL thickness.