Multi-centre variability of ISCEV standard ERGs in two normal adults

Area of Science:

• Ophthalmology
• Neuroscience
• Biomedical Engineering

Background:

• Reproducibility of full-field electroretinograms (ERGs) between different clinical centers has not been previously evaluated.
• Assessing inter-center variability is crucial for establishing reliable diagnostic standards in ophthalmology.

Purpose of the Study:

• To investigate the reproducibility of full-field ERGs across multiple centers.
• To compare the variability of ERGs recorded using local versus a standardized ISCEV (International Society for Clinical Electrophysiology of Vision) protocol.
• To determine if standardization enhances ERG reliability.

Main Methods:

• Electroretinograms (ERGs) were recorded from two subjects at 15 UK centers using both silver thread and skin electrodes.
• Recordings were performed using routine local protocols and a standardized ISCEV-specified protocol.
• Variability was assessed for amplitude and peak time across centers and protocols.

Main Results:

• Inter-center ERG variability was generally small and within clinically significant thresholds.
• Amplitude variability was lower with local LED protocols compared to the ISCEV-specified xenon flash protocol.
• Peak time variability was lower with the ISCEV-specified protocol, suggesting improved standardization benefits.

Conclusions:

• Inter-center variability in ERGs is often within acceptable clinical limits, especially with appropriate standardization.
• The existing ERG standard is vindicated, and further standardization could improve global ERG reproducibility.
• Standardization efforts should consider the impact of equipment like xenon flashtubes on overall variability.