Abnormalities in saccade dynamics in first-episode treatment-naive hyperthyreosis patients with no pre-existing eye damage: a primary exploratory study

Objective: To explore the potential difference of eye saccade dynamics between first-episode treatmentnaïve hyperthyreosis patients without pre-existing eye damage and healthy controls by using basic visually guided saccade (VGS). Methods: 15 hyperthyroidism outpatients and 15 healthy controls participated in VGS analysis. Multiple indicators, including amplitude, duration, latency, main sequence analysis was performed to evaluate the differences of peak velocity (PV) and duration between the groups and general linear model was used to find the differences on latency, peak acceleration and peak deceleration between the groups. Results: There was a statistically significant difference in Vmax values between hyperthyreosis patients and healthy controls (438.47 ± 55.46°/s in control group and 486.10 ± 51.49°/s in hyperthyroidism group, Mann-Whitney U test, Z = -2.053, P = 0.040). GLM-based analysis showed that when amplitude = 10.819°, PV = 311.587°/s, duration = 61.94 ms, the saccade latency showed significant differences between hyperthyreosis patients (223.364 ms, 95% confidence interval (CI) = [219.245, 227.482]) and healthy controls (234.601 ms, 95% CI = [230.497, 238.705]); the peak acceleration showed significant differences between hyperthyreosis patients 14127.205°/s2 (95% CI = [14061.606, 14192.804]) and healthy controls (13959.973°/s2, 95% CI = [13894.610, 14025.337]); the peak deceleration showed no significant differences between hyperthyreosis patients (-10160.784°/s2, 95% CI = [-10263.189, -10058.378]) and healthy controls (-10194.008°/s2, 95% CI = [-10296.046, -10091.970]). Conclusion: Compared to healthy controls, hyperthyreosis patients displayed different dynamics in eye movement during VGS. Saccade tracking examination has a potential value for early detection of thyroid-associated ophthalmopathy.