A full-field (Ganzfeld) electroretinogram (ERG) is performed on a patient with suspected retinitis pigmentosa. The 30 Hz flicker response is markedly delayed and reduced. Which retinal cell type primarily generates the a-wave of the standard full-field ERG?
- A Photoreceptors (rods and cones) ✓
- B Retinal ganglion cells
- C Bipolar cells
- D Retinal pigment epithelium
Correct answer: A. Photoreceptors (rods and cones)
Explanation
The a-wave of the full-field ERG is generated primarily by photoreceptor hyperpolarization in response to light. The b-wave arises from bipolar and Müller cell activity. Ganglion cells contribute to the pattern ERG, not the full-field flash ERG. The RPE generates the c-wave, which is not routinely recorded in standard clinical flash ERG.
Reference: Principles and Practice of Clinical Electrophysiology of Vision, Heckenlively and Arden, 2nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.