Visual acuity is greatest at the fovea centralis compared with all other retinal regions. Which structural feature best explains this?
- A Presence of rods with high convergence onto ganglion cells
- B Displacement of overlying retinal layers with nearly one-to-one cone to ganglion cell connections ✓
- C Highest density of blood vessels supplying the photoreceptors
- D Presence of large receptive fields served by many photoreceptors per ganglion cell
Correct answer: B. Displacement of overlying retinal layers with nearly one-to-one cone to ganglion cell connections
Explanation
The fovea contains only cones, and its inner retinal layers are displaced laterally so light strikes photoreceptors directly with minimal scattering. Each foveal cone connects through few bipolar cells to a single ganglion cell, giving very small receptive fields and high resolution. High convergence and large receptive fields improve sensitivity but reduce acuity, and the fovea is avascular, receiving supply from the choriocapillaris.
Reference: Ganong's Review of Medical Physiology, 26th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.