Clinical applications of multifocal electroretinography

Area of Science:

• Ophthalmology
• Neuroscience
• Visual Electrophysiology

Background:

• The multifocal electroretinogram (mfERG) is a valuable tool for assessing localized retinal function.
• Traditional full-field ERGs provide limited information about regional visual field defects.

Purpose of the Study:

• To evaluate the utility of the m-sequence multifocal ERG for detailed analysis of retinal function.
• To investigate the correlation between mfERG findings and visual field defects in various retinal disorders.

Main Methods:

• Utilized the m-sequence stimulation technique to record 61-241 local ERG signals within a 4-16 minute timeframe.
• Performed recordings in a light-adapted state to isolate cone-driven responses.
• Analyzed ERG amplitudes and implicit times to characterize retinal function.

Main Results:

• mfERG accurately described regional functional losses in outer retinal layers, comparable to cone responses.
• Identified decreased or absent central ERGs in maculopathies, allowing estimation of lesion extent.
• Demonstrated a similar distribution pattern between mfERG activity and visual field defects in outer retinal diseases.
• Observed delayed implicit times in conditions like retinitis pigmentosa and retinal edema (CRVO, cystoid macula edema).
• Found no simple correlation between mfERG and field defects in ganglion cell layer disorders.

Conclusions:

• mfERG is highly effective for detailed assessment of localized retinal dysfunction.
• Implicit time delays are significant indicators of specific retinal pathologies.
• mfERG aids in the differential diagnosis of retinal and optic nerve diseases.