Which region shows the greatest convergence of rods onto rod bipolar cells?

• A. Fovea
• B. Near fovea
• C. Far peripheral retina
• D. Near peripheral retina

Answer: (C)

Rods pool their signals through rod bipolar cells, and the density of rods is highest in the far peripheral retina. That means lots of rods feed into relatively few rod bipolar cells there, creating the greatest convergence. This high convergence boosts sensitivity in low light but trades off fine detail. In the fovea and near the fovea, rods are sparse or absent (cones dominate), so there’s little to no rod input and thus minimal convergence of rods onto rod bipolar cells. Near peripheral retina has more rods than the fovea but fewer than the far periphery, so the convergence is intermediate. So the far peripheral retina shows the greatest convergence of rods onto rod bipolar cells.