Graves disease (GD) is autoimmunological disorder leading most often to hyperthyroidism and invasive-edema opthalmopathy (Graves opthalmopathy GO).
Aim: Estimation of the relation of visual evoked potentials (VEP) results with the indicators of activity and advancement of the progress of GO.
Materials and methods: The examined group consisted of 45 patients between the age of 24 and 77, hospitalized in the Department of Endocrinology and Metabolism. Duration of GD from the first clinical signs to the start of treatment took between 3 months to 20 years. Changes of the eye due to GO occurred from 3 months to 6 years. VEPs were carried out according to recommendations of the International Federation of Clinical Neurophysiology. Latencies and amplitudes of VEP components were compared to normal values.
Results: According to the NOSPECS scale 2 people showed no visual symptoms. In 5 cases, class 1 or 2 was diagnosed. Furthermore, in 38 patients classes between 3 and 6 were observed. Possible loss of vision due to visual nerve damage (class 6) was found in only 4 patients. The CAS criteria in 8 patients was equal to 0, and the remaining 14 patients from 1 to 3. Active GO was diagnosed in 23 patients. In 35 (77.8%) patients, abnormal VEPs were recorded. Normal parameters of VEP were observed in only 10 (22.2%) patients. These were patients with inactive or mild processes involving eye balls. Changes in latency of P100 increased from 123 ms in mild, to 127 ms in intermediate, to 129 ms in intense GO. Referring to the control group a statistical change was observed in latency of P100 and N145. They were extended already in mild occurrence of GO which confirmed subclinical visual nerve involvement.
Conclusions: VEP can be helpful in diagnosing visual nerve neuropathy in patients with GD. The clinical interpretation of changes of P100 latency is very important in patients with GO.