Evaluation of ocular pulse amplitude in patients with carotid artery stenosis using the Pascal dynamic contour tonometer

Abstract

Background: To evaluate ocular pulse amplitude (OPA) in patients with carotid artery stenosis (CAS) using the Pascal dynamic contour tonometer (DCT).

Methods: Consecutive patients who underwent ultrasound Doppler examination of the carotid artery for the suspicion of CAS were prospectively enrolled in the study. Each patient underwent a complete ocular examination. OPA was measured using Pascal DCT. The participants were divided into four groups according to the degree of CAS: Group 1 (no occlusion, control group), Group 2 (mild occlusion: < 50 per cent), Group 3 (moderate occlusion: 50-69 per cent), and Group 4 (severe occlusion: ≥ 70 per cent).

Results: A total of 161 eyes of 81 patients were included in the study. Of the 81 patients, 50 (61.7 per cent) were male, and 31 (38.3 per cent) were female. The mean age was 66.6 ± 12.3 years (range, 20-91 years). Mean OPA values were found to be 2.68 ± 0.97 mmHg in Group 1 (n = 64 eyes), 2.62 ± 0.83 mmHg in Group 2 (n = 49 eyes), 2.30 ± 0.97 mmHg in Group 3 (n = 27 eyes) and 1.66 ± 0.59 mmHg in Group 4 (n = 21 eyes). There was no statistically significant difference in mean OPA levels between Group 1 and Group 2 (p = 0.73). However, statistically significant differences were found between the other groups when they were compared with each other (Groups 1 and 3, p = 0.02; Groups 1 and 4, p < 0.001; Groups 2 and 3, p = 0.02; Groups 2 and 4, p < 0.001; Groups 3 and 4, p = 0.002).

Conclusion: OPA decreases in patients with moderate to severe CAS. OPA measurement with Pascal DCT can be used as a screening test for CAS.

Keywords: Doppler ultrasonography; carotid artery stenosis; dynamic contour tonometry; ocular pulse amplitude; stroke.