Exploration of multifocal rod electroretinograms recording in human.
OBJECTIVE
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.
Chen
Changzheng
C
Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou 510060, China.
Wu
Lezheng
L
Wu
De-Zheng
DZ
Long
Shixian
S
Liang
Jiongji
J
Jiang
Futian
F
Jiang
Libing
L
D000328:Adult; D003623:Dark Adaptation; D004596:Electroretinography / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012160:Retina / Q000033:anatomy & histology; D017948:Retinal Rod Photoreceptor Cells / Q000502:physiology*; D014794:Visual Fields