Subclinical optic neuropathy in Graves' orbitopathy.

PURPOSE The aims of the study were to detect early changes in the optic nerve function of patients with Graves' orbitopathy (GrO) who do not have any signs and symptoms of optic neuropathy, using pattern visual evoked potentials (P-VEP), and investigate any possible relation between the disease activity and P-VEP P100 latencies of the patient group. METHODS The study was conducted in a tertiary care hospital. Sixteen patients with GrO and 15 healthy controls were enrolled. P-VEP P-100 latencies were compared between these two groups. Correlation between the clinical disease activity and P-VEP P-100 latencies of the patient group was also investigated. RESULTS Mean P-VEP P-100 latency values were significantly different in the GrO (122.0+/-14.40 ms) and control groups (105.9+/-7.7 ms) (P=.0004). The GrO patients' P-100 latencies correlated mildly with their activity scores (r=.364, P=.0406). CONCLUSIONS Clinical application of the P-VEP for the assessment of visual function in patients with GrO proved useful for early diagnosis of the optic nerve involvement, and it may be more valuable in patients with "active" congestive disease.