Slope between positive and negative ERG components in patients with open-angle glaucoma

Area of Science:

• Ophthalmology
• Neuroscience
• Medical Imaging

Background:

• Glaucoma is a leading cause of irreversible blindness.
• Retinal ganglion cell (RGC) dysfunction is a hallmark of glaucoma.
• Standard electroretinography (ERG) measures retinal function, but specific RGC dysfunction markers require further investigation.

Purpose of the Study:

• To assess the diagnostic utility of specific ERG waveform slopes in identifying RGC dysfunction in open-angle glaucoma.
• To compare the P50-N95 slope of the pattern electroretinogram (PERG) and the b-PhNR slope of the light-adapted (LA) ERG.

Main Methods:

• Retrospective analysis of PERG and LA-ERG traces from 16 open-angle glaucoma patients and 21 controls.
• Quantification of the P50-N95 and b-PhNR slopes using linear regression analysis.
• Correlation analysis between ERG slopes and other ERG components (PhNR, N95, b-wave amplitudes).

Main Results:

• The P50-N95 slope was significantly less steep in glaucoma patients compared to controls (p < 0.001).
• The b-PhNR slope did not differ significantly between glaucoma patients and controls (p = NS).
• The P50-N95 slope strongly correlated with PhNR and N95 amplitudes, while the b-PhNR slope correlated with b-wave amplitude.

Conclusions:

• The P50-N95 slope is a sensitive electrophysiological marker for RGC dysfunction in open-angle glaucoma.
• The b-PhNR slope appears less sensitive to glaucomatous RGC dysfunction and may reflect different retinal pathways.
• ERG waveform analysis offers potential for early glaucoma detection and monitoring.