Abstract
Purpose: :
Clinical dysthyroid optic neuropathy, although infrequent, is one of the most serious complications of Graves’s ophthalmopathy (GO). The aim of this study was to investigate by means of the multifocal visual evoked potentials (mfVEP) early neuropathic changes in GO patients without any clinical symptoms of dysthyroid optic neuropathy (NO) in order to evaluate the prevalence of subclinical optic neuropathy.
Methods: :
Static automated perimetry (Humphrey, Zeiss), optic coherence tomography (Stratus 3.0, Zeiss) and mfVEP recordings (Veris 5.4, EDI) were obtained in thirty four patients with GO without any clinical signs of dysthyroid ON and in twenty healthy controls.
Results: :
mfVEP latencies were significantly delayed in the GO group (fifteen patients) in comparison with controls. mfVEP amplitudes were also significantly reduced in the GO group (nine patients) when compared with the healthy group. Consistent visual field defects were shown in up to thirty per cent of GO patients, however, the change in the mfVEP amplitudes or latencies did not agreed with the visual field findings with regard to topography when present. Retinal nerve fiber layer (RNFL) measurements in the GO group did not differ significantly from the control group and it did not show any correlation with the mfVEP amplitudes or latencies changes.
Conclusions: :
The assessment of mfVEP latencies and amplitudes in Graves’ ophthalmopathy patients is a very sensitive and objective indicator of incipient optic neuropathy in the clinic.
Keywords: electrophysiology: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • neuro-ophthalmology: diagnosis