PURPOSE: To test the feasibility of recording rod multifocal electroretinograms (ERG) in humans and observe appropriate recording conditions. METHODS: Multifocal rod ERG were recorded using a stimulus array of 61 equalsized hexagons in two normal subjects after the dark adaptation. Flashes were blue (W47B). Blank frames between two successive flashes of hexagons varied from 0 to 14. Length of the m-sequence, bandwidth, flash frequency, flash intensities and background intensities were changed to obtain appropriate recording conditions for the clinical use. RESULTS: Multifocal rod ERG were clearly recordable and well formed. They had an early implicit time, very small negative wave and a late implicit time, large positive wave. The positive wave was bimodal, whose timing and waveform were similar to the full-field rod ERG. The local response amplitudes can be suppressed with increase in flash frequency or background intensity, decrease in flash intensity or the size of stimulus elements. CONCLUSIONS: Multifocal rod ERG can be recorded in human and can provide topographical maps of retinal function that have clinical usage. 2(12)-1 m-sequence length, 3F blank frames and 3 - 300 Hz bandwidth were suggested to appropriate recording conditions.
PURPOSE: To test the feasibility of recording rod multifocal electroretinograms (ERG) in humans and observe appropriate recording conditions. METHODS: Multifocal rod ERG were recorded using a stimulus array of 61 equalsized hexagons in two normal subjects after the dark adaptation. Flashes were blue (W47B). Blank frames between two successive flashes of hexagons varied from 0 to 14. Length of the m-sequence, bandwidth, flash frequency, flash intensities and background intensities were changed to obtain appropriate recording conditions for the clinical use. RESULTS: Multifocal rod ERG were clearly recordable and well formed. They had an early implicit time, very small negative wave and a late implicit time, large positive wave. The positive wave was bimodal, whose timing and waveform were similar to the full-field rod ERG. The local response amplitudes can be suppressed with increase in flash frequency or background intensity, decrease in flash intensity or the size of stimulus elements. CONCLUSIONS: Multifocal rod ERG can be recorded in human and can provide topographical maps of retinal function that have clinical usage. 2(12)-1 m-sequence length, 3F blank frames and 3 - 300 Hz bandwidth were suggested to appropriate recording conditions.