Abstract
Purpose :
To describe the changes in oscillatory potential (OP) magnitude with changing light-adapted full-field electroretinogram stimulus sizes.
Methods :
This study was an additional analysis using data that has been collected and published for a previous study (Doc Ophthalmol, 142:213-231). Six healthy human subjects (5 male, 1 female) underwent electroretinographical measurements using two stimulus conditions, red flash on blue background (RoB) and white flash on white background (WoW). A Ganzfeld stimulator was used to generate flash stimuli of varying sizes under both RoB and WoW conditions, including full-field and circular stimuli of 70-, 60-, 50-, 40-, 30-, and 20-degrees diameter. For this study, OP tracings were extracted from ERG output of both RoB and WoW stimuli using a Butterworth digital high-pass filter with two cutoffs: 58 Hz and 100 Hz. OP magnitudes were calculated using the root mean square (RMS) of the peak amplitudes. OP RMS was plotted against stimulated retinal area in GraphPad Prism. For all four combinations of stimulus conditions and filter frequencies, exponential equations were fitted to the data to obtain correlation coefficients and a constant (K) that describes the initial amplitude change.
Results :
When OPs were obtained by filtering at 58 Hz and at 100 Hz, RMS amplitudes and stimulated retinal area were strongly and positively correlated. Large correlation coefficients were obtained for tracings filtered at 58 Hz (WoW: R2=0.9978; RoB: R2=0.9979) and at 100 Hz (WoW: R2=0.9968; RoB: R2=0.9996). There was no significant difference in the K values between WoW and RoB stimulus conditions.
Conclusions :
The correlation between OP RMS amplitudes and stimulus area was very similar for both cutoffs of the digital filter and between the two stimulus conditions. Furthermore, the R2 values were higher compared to any other ERG parameters evaluated in the previous study, indicating stronger spatial integration in OP generating mechanisms.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.