Check-size specific changes of pattern electroretinogram in patients with early open-angle glaucoma

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Science

Background:

• Open-angle glaucoma is a leading cause of irreversible blindness.
• Early detection of glaucomatous visual field defects is crucial for timely intervention.
• The pattern electroretinogram (PERG) assesses the function of the inner retina, particularly ganglion cells.

Purpose of the Study:

• To investigate the sensitivity of the pattern electroretinogram (PERG) in detecting early-stage open-angle glaucoma.
• To explore the differential effects of check size on PERG amplitude in glaucoma patients compared to normal subjects.

Main Methods:

• Recorded pattern electroretinogram (PERG) in patients with early open-angle glaucoma and age-matched controls.
• Utilized counterphasing checkerboard patterns of varying check sizes (0.8 to 15 degrees) at 7.8 Hz.
• Assessed visual acuity, ensuring all participants had acuity above 0.8.

Main Results:

• Glaucoma patients exhibited significantly reduced PERG amplitudes for small check sizes (p = 0.003).
• PERG amplitudes were nearly normal for large check sizes in glaucoma patients.
• The ratio of amplitudes between small and large checks was significantly lower in glaucoma patients (p < 0.0002).

Conclusions:

• The pattern electroretinogram (PERG) is a sensitive indicator of early ganglion cell dysfunction in open-angle glaucoma.
• Differential responses to small and large check sizes suggest involvement of magnocellular and parvocellular pathways.
• Using the ratio of small-to-large check size amplitudes enhances PERG's diagnostic sensitivity and reduces variability.