The photopic negative response of the Light-adapted 3.0 ERG in clinical settings
Ortiz G, Drucker D, Hyde C, Staffetti J, Kremers J, Tzekov R (2019)
Publication Type: Journal article
Publication year: 2019
Journal
DOI: 10.1007/s10633-019-09723-5
Abstract
Purpose To analyze the effects of different methods of measurement on the photopic negative response (PhNR), recorded as part of a standard ISCEV Photopic 3.0 ERG responses from patients with a variety of clinical diagnoses. Methods ERGs were recorded from both eyes of 97 patients (187 eyes) as part of a standard clinical assessment. The average age was 56.4 +/- 15.7 years, the gender balance was 35 M, 62F, and only recordable responses of acceptable quality were included. PhNR was measured at an identifiable trough before (PhNR1) and after the i-wave (PhNR2), and the amplitudes and peak times were compared with a-, b- and i-wave corresponding parameters. PhNR components were measured: from baseline and from b-wave peak. Correlation between PhNR troughs and with ERG parameters were tested for right eyes. The possibility to predict and substitute PhNR2 amplitude from PhNR1 amplitude was also tested. Results PhNR1 was recordable in 97.3% of eyes and PhNR2 in 85.6%. An identifiable PhNR2 peak was found to occur before 65 ms at similar to 50% of the records, while in similar to 38% of the cases was within 65-75 ms in similar to 12%-after 75 ms. The correlation between the PhNR1 and PhNR2 peaks was quite strong (with coefficients 0.81-0.98, depending on method of measurement, and slopes close to 1). The average difference between predicted and measured PhNR2 was reasonably small in absolute (< 2 mu V) and relative (< 2%) terms. The correlations between PhNR amplitudes and other ERG component amplitudes showed different ranges of correlation coefficients depending on the method of measurement: for the a-wave amplitudes the range of coefficients was 0.48-0.73, while for the b-wave amplitudes it was 0.30-0.95 and 0.39-0.65 for i-wave. Conclusion The strong correlation between the two PhNR troughs could allow using PhNR1 when PhNR2 is poorly defined due to artifacts. Different methods of PhNR measurement lead to different correlations with other ERG parameters, and this needs to be considered when analyzing and comparing PhNR data between studies.
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APA:
Ortiz, G., Drucker, D., Hyde, C., Staffetti, J., Kremers, J., & Tzekov, R. (2019). The photopic negative response of the Light-adapted 3.0 ERG in clinical settings. Documenta Ophthalmologica. https://doi.org/10.1007/s10633-019-09723-5
MLA:
Ortiz, Gonzalo, et al. "The photopic negative response of the Light-adapted 3.0 ERG in clinical settings." Documenta Ophthalmologica (2019).
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