Application of electrophysiological tests in the evaluation of early thyroid-associated ophthalmopathy.

PURPOSE

To compare the electrophysiology between mild thyroid-associated ophthalmopathy (TAO) patients and normal population.

METHODS

The present research was a retrospective observational study and enrolled consecutive patients diagnosed with mild TAO according to European Group on Graves's Orbitopathy with corrected to normal vision. Full-field electroretinography, pattern visual evoked potential (PVEP) and isolated-check visual evoked potential (icVEP) were performed for TAO patients and age-matched normal subjects.

RESULTS

Thirty-two eyes with mild TAO and forty-six eyes from normal subjects were included. Statistically significant increase in the amplitude of dark-adapted 0.01, 3 and 10 ERG and total oscillatory potentials and light-adapted 3 and 30 Hz flicker ERG were observed in TAO patients compared with the normal subjects, but not the latency. No significant difference was observed in the P100 amplitude or latency in 1° and 15' PVEP between TAO patients and normal subjects. The signal-to-noise ratio (SNR) was not significantly different in TAO patients at the contrast of 1%, 2%, 8%, 16% or 32% icVEP, and the SNR in contrast 4% icVEP was significantly smaller in TAO patients compared to normal subjects.

CONCLUSION

Mild TAO patients can have electrophysiological changes that might indicate neural changes in the early disease phase.