Photopic negative response versus pattern electroretinogram in early glaucoma

Area of Science:

• Ophthalmology
• Neuroscience
• Electrophysiology

Background:

• Retinal ganglion cell (RGC) dysfunction is a hallmark of glaucoma.
• Photopic negative response (PhNR) and pattern electroretinogram (PERG) are electrophysiological measures of RGC function.
• Both PhNR and PERG are known to be reduced in glaucoma patients.

Purpose of the Study:

• To compare the diagnostic performance of PhNR and PERG in different stages of glaucoma.
• To evaluate both amplitude and ratio measures for PhNR and PERG.
• To assess the utility of combining PhNR and PERG for glaucoma detection.

Main Methods:

• Included were 11 eyes with preperimetric glaucoma, 18 with manifest glaucoma, and 26 normal controls.
• PhNR and steady-state PERG were recorded.
• Analysis included PhNR amplitude, PhNR/b-wave ratio, PERG amplitude, and PERG ratio (0.8°/16°).

Main Results:

• PhNR identification was reliable at flash strengths ≥1 cd·s/m(2).
• Both PhNR and PERG amplitudes and ratios were reduced in preperimetric and manifest glaucoma compared to normals.
• Receiver operating characteristic (ROC) analysis showed that ratios performed better than amplitudes, particularly when combining PhNR and PERG for diagnosis.

Conclusions:

• Both PhNR and PERG are effective electrophysiological tools for glaucoma detection.
• Ratio measures of PhNR and PERG demonstrate superior diagnostic accuracy compared to amplitude measures.
• Combining PhNR and PERG provides high diagnostic accuracy across glaucoma stages, with PhNR offering advantages in suboptimal optical conditions.