Impact of a Digital Power Line Filter in the 2-Global-Flash Multifocal Electroretinogram of XXXX @entity1 Compared to Controls.

@entity1 @entity725 @entity726
PURPOSE: To assess the effect of a 50   Hz power line digital filter on the response to a 2-global-flash multifocal electroretinogram (mfERG) in @entity725 ( @entity725 ) compared to control. MATERIALS AND METHODS: A 2-global-flash mfERG (VERIS   ) was recorded (23 control, 34 @entity725 ). Eight recordings were noise contaminated: 4 control, 4 @entity725 . Response averages from the central 10   and 7 surrounding groups were analyzed with and without a 50   Hz digital filter for the following mfERG response epochs: direct component (15-45   ms), 1st (45-75   ms) and 2nd (75-105   ms) induced components. RESULTS: A digital 50   Hz filter had little effect on uncontaminated with noise waveforms but, in noisy recordings, changed the waveform dramatically to resemble uncontaminated waveforms. In controls' 50   Hz-filtered uncontaminated with noise mfERGs differed significantly from unfiltered responses in induced components. Uncontaminated with noise recordings from @entity726 @entity1 did not differ with or without the notch filter (p   >   0.1 for all three epochs of mfERG). The mfERG response in the central 10  in @entity726 @entity1 differed significantly from controls, whether the notch filter was used or not (p   <   0.001). CONCLUSIONS: A 50   Hz notch filter allows grossly contaminated waveforms to be analyzed in a meaningful manner. With a 50   Hz filter, @entity726 @entity1 still differed significantly from normal.
