Visual Evoked Potentials (VEP) in Graves’ Disease Patients in Siriraj Hospital

Abstract

Objective: To evaluate the visual evoked potentials (VEP) in Graves’ disease patients in order to reveal the possible presen- tation of subclinical optic neuropathy.
Methods: Forty-seven Graves’ disease patients without symptoms of optic neuropathy were enrolled. Flash visual evoked potentials (F-VEP) and Pattern visual evoked potentials (P-VEP) were evaluated. Comparison of VEP with normal values was done, between the groups with and without the presentation of eye sign(s) and also among the groups that had differ- ences in thyroid hormone function.
Results: The mean F-VEP amplitude and latency were 17.56±6.20 microvolts (μV) and 114.02±14.92 milliseconds (ms), respectively. The mean P-VEP amplitude and latency were 10.82±4.88 μV and 99.67±5.87 ms, respectively. These values were within normal values. Only the latency of P-VEP was increased significantly (P<0.001) when compared between the groups with (101.81±5.70 ms) and without eye signs (97.43±5.21ms) and it also increased significantly (P=0.033) when compared with normal values. The hyperthyroid group also had a significant increase in the latency of P-VEP when compared to other groups (P=0.002).
Conclusion: Increase in the latency of P-VEP should be sought for and reminded the clinician to conduct close follow-up of this as an early sign of optic neuropathy, especially in the patients with eye manifestation.