Which waveform is associated with offset of the stimulus in a photopic ERG?

Which waveform is associated with offset of the stimulus in a photopic ERG?

• A. A-wave
• B. B-wave
• C. C-wave
• D. D-wave

Answer: (D)

In a photopic ERG, responses are tied to timing relative to the light stimulus, with distinct parts for onset and offset. The A-wave comes from photoreceptors at light onset, and the B-wave mainly reflects ON-bipolar (and Müller cell) activity that follows. When the light goes off, the fastest offset signal in a photopic response is the D-wave—the immediate deflection as cone-driven signaling terminates. The C-wave is a slower, longer-lasting change linked to outer retinal and RPE activity and is more prominent under certain stimulus conditions, but it is not the immediate offset component. So the waveform tied to the stimulus offset in a photopic ERG is the D-wave.

In a photopic ERG, responses are tied to timing relative to the light stimulus, with distinct parts for onset and offset. The A-wave comes from photoreceptors at light onset, and the B-wave mainly reflects ON-bipolar (and Müller cell) activity that follows. When the light goes off, the fastest offset signal in a photopic response is the D-wave—the immediate deflection as cone-driven signaling terminates. The C-wave is a slower, longer-lasting change linked to outer retinal and RPE activity and is more prominent under certain stimulus conditions, but it is not the immediate offset component. So the waveform tied to the stimulus offset in a photopic ERG is the D-wave.