Effect of 50-Hz Filters on Pattern Electroretinogram

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Pattern electroretinogram (PERG) assesses retinal ganglion cell function.
• PERG signals are often small, posing challenges for accurate examination.
• Waveform noise can be mitigated using signal filters.

Purpose of the Study:

• To investigate the impact of 50-Hz filters on pattern electroretinogram (PERG) test outcomes.
• To evaluate how different intensities of 50-Hz filters affect PERG parameters.

Main Methods:

• Retrospective observational study analyzing 24 PERG waveforms.
• PERG tests conducted using the RETI-scan system per ISCEV guidelines.
• Application of three 50-Hz filter types (soft, middle, hard) to analyze parameter differences.

Main Results:

• Significant reduction (8-15%) in P50 and N95 amplitudes after filtering, more pronounced in normal subjects.
• No significant differences observed in latencies, except for N35 peak time.
• N95/P50 ratio decreased with middle and hard 50-Hz filters; minimal shifts between normal/abnormal classifications.

Conclusions:

• 50-Hz filters effectively reduce PERG waveform noise.
• While peak times remain unaffected, amplitudes are significantly reduced.
• Clinical interpretation of PERG requires caution when employing 50-Hz filters.