Flash and pattern visual evoked potentials in the diagnosis and monitoring of dysthyroid optic neuropathy

Abstract

SUMMARYFlash and pattern visual evoked potentials were recorded in 8 patients (13 eyes) with dysthyroid optic neuropathy (DON), diagnosed using the American Thyroid Associ ation classification. All were treated with systemic ster oids, but 4 patients (6 eyes) also required orbital decompression. Flash YEP (P2) and pattern YEP (PI00) were recorded prior to and 2 weeks after commencing steroid treatment or decompression. Fifteen patients with Graves orbitopathy but without DON, and 20 healthy subjects, acted as controls. Before treatment visual acuity was reduced in 10 eyes and visual fields were abnormal in 5, but the YEP was abnormal in all 13, with the group mean amplitude of P2 and PI00 significantly less than controls, and the group mean PIOO latency significantly greater than controls. After treatment with high-dose steroids or surgical decompression there were significant improvements in the group mean amplitude of P2 and PIOO, and significant reductions in P2 and PIOO latency; however, individually, improvements in amplitude were more significant than improvements in latency. We con clude that the YEP to flash and pattern stimuli provides a useful diagnostic and monitoring tool in patients with DON, combining objectivity with quantitative analysis.

Course of pattern-reversed visual evoked cortical potentials in 30 eyes after bony orbital decompression in dysthyroid optic neuropathy

“…While Tsaloumas and co-workers reported on immediate mean latency recovery 2 weeks after orbital decompression in seven eyes with DON using pattern-reversed stimuli, Setälä and associates observed indiscriminate mean flash-evoked cortical response latencies after 7 years of follow-up in seven patients 10 11. This is in line with our findings after a mean follow-up of 10 months: latencies did not reveal significant regeneration and even deteriorated in some patients after bony orbital decompression.…”

“…Tsaloumas et al compared pattern- and flash-evoked VECP during radiation and decompression therapy and concluded that there were no substantial differences between the techniques 11. However pattern-evoked VECP may be affected by patient compliance, media opacity or blurred vision primarily impairing amplitude potentials, while latencies remain unaffected or may be compromised to a much lesser extent as long as retinal luminance remains unaffected 11 20. Although our patients underwent systemic steroid treatment, significant cataract formation during the VECP follow-up period was not observed.…”

Clinical features of dysthyroid optic neuropathy: a European Group on Graves' Orbitopathy (EUGOGO) survey

“…17 In this study VEPs were performed in less then a third of patients, reflecting variation in facilities rather that the efficacy of the test. Results were abnormal in 8 out of 11 definite cases of DON.…”

Using frequency-doubling perimetry to detect optic neuropathy in patients with Graves’ orbitopathy

“…In a study by Neigel et al 1 involving 58 patients with DON, 64% had abnormal color vision and 66% had abnormal fi elds, whereas the pattern VEP was abnormal in 94%. Tsaloumas et al 22 studied 13 eyes of eight patients with DON and found abnormal VEP before treatment in all 13 eyes, with a signifi cant improvement after treatment with high-dose steroids or surgical decompression. The authors concluded that VEP to fl ash and pattern stimuli provides a useful diagnostic and monitoring tool in patients with DON.…”