Which ERG technique records photopic responses from multiple retinal locations?

• A. Pattern ERG
• B. Full-field ERG
• C. Multifocal ERG
• D. Oscillatory potentials

Answer: (A)

Multifocal ERG is used to map photopic (cone-driven) responses across many retinal locations. It presents an array of small stimuli that flicker in sequence, so the electrical responses from different retinal areas can be extracted and plotted as a topographic map of function. This spatially resolved approach is what lets you see how cone function varies across the retina, not just a single central area or a global average.

Pattern ERG, while photopic, mainly reflects activity from the central retina and ganglion cells in the macula, yielding a single waveform rather than a map of multiple locations. Full-field ERG records the summed response from the entire retina, providing one global waveform rather than localized data, and oscillatory potentials are high-frequency components within that global response.