Clinical Usefulness of Fresnel Ganzfeld Stimulator

ABSTRACT

PURPOSE: To compare electroretinogram (ERG) waveforms acquired using a ganzfeld stimulator and a Fresnel ganzfeld stimulator. METHODS: ERGs were recorded with a ganzfeld stimulator and a Fresnel ganzfeld stimulator from both eyes of 25 volunteers. Peak-to-trough amplitudes and peak implicit times were compared between both eyes and between a ganzfeld stimulator and a Fresnel ganzfeld stimulator. ERGs taken from the sitting and supine positions were also compared using the Fresnel ganzfeld stimulator. RESULTS: There was no statistically significant difference between the Fresnel ganzfeld stimulator and dome-shaped ganzfeld stimulator in amplitude and implicit time of dark adapted 0.01, 3.0 ERG, photopic 3.0 ERG, photopic 3.0 flicker. The differences in amplitude and implicit time between the right and left eyes were not influenced by the Fresnel ganzfeld stimulator. Additionally, no differences were observed in ERGs obtained from the sitting and supine positions using the Fresnel ganzfeld stimulator. CONCLUSIONS: The newly developed ganzfeld stimulator with a sealed Fresnel lens can be considered as a reliable alternative method for measuring ERGs. Fresnel ganzfeld stimulator is useful for patients having problems with mobility or uncooperative children.