This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Purchase Article View Shopping Cart Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Salvi, M. Articles by Roti, E. Search for Related Content PubMed PubMed Citation Articles by Salvi, M. Articles by Roti, E.

The Study of Visual Evoked Potentials in Patients with Thyroid-Associated Ophthalmopathy Identifies Asymptomatic Optic Nerve Involvement¹

Centro per lo Studio, Prevenzione, Diagnosi e Cura delle Tireopatie, Istituto di Oftalmologia (E.S., F.N., C.M.) and Radiologia (F.F.), Università di Parma, Parma, Italy; and Thyroid-Eye Research Program, Allegheny-Singer Research Institute (J.R.W.), Pittsburgh, Pennsylvania 15212-4772

Address all correspondence and requests for reprints to: Dr. Mario Salvi, Cattedra di Endocrinologia, Università di Parma, via Gramsci 14, 43100 Parma, Italy.

In the present study we have recorded visual evoked cortical potentials (VECP) in 88 patients affected by autoimmune thyroid disease and thyroid-associated ophthalmopathy (TAO) without clinical signs of optic neuropathy. At the time of ophthalmological examination, 37 of these patients were hyperthyroid, 41 were euthyroid, and 8 were hypothyroid; 2 were not assessed. Twenty-nine normal subjects served as controls. We performed pattern reversal visual stimulation and recorded the amplitude and latency of the cortical electric response at 100 ms (P100 wave). There were no differences in the mean P100 amplitude of TAO patients and normal subjects. The mean P100 latency in patients was 105.6 ± 0.5 ms, significantly higher than that in normal subjects (102.0 ± 0.5 ms; P < 0.00003). Latency in euthyroid patients did not differ from that in either hypo- or hyperthyroid patients. The VECP test was positive (latency, 110.0 ms) in 21 (23.8%) TAO patients. In patients with proptosis greater than 21 mm, latency was 106.7 ± 0.7 ms, significantly higher than that in patients with normal Hertel measurements (104.3 ± 0.6 ms; P < 0.01). Latency was not increased in patients with acute inflammatory signs compared to those with inactive eye disease and in patients with altered extrinsic motility. In patients with an abnormal visual field study, the mean latency was 110.3 ± 1.5 ms, significantly higher than that in patients with a normal visual field (104.7 ± 0.4; by t test, P < 0.000003). In conclusion, we observed a prolongation of the latency of the evoked cortical response in patients with TAO without subjective visual complaints and without optic nerve compression. We believe that the study of VECP in TAO is complementary to the study of the visual field in identifying early optic nerve dysfunction in the absence of decreased visual acuity.

This article has been cited by other articles:

				L. Bartalena, A. Pinchera, and C. Marcocci Management of Graves' Ophthalmopathy: Reality and Perspectives Endocr. Rev., April 1, 2000; 21(2): 168 - 199. [Abstract] [Full Text]