Near the fovea, each rod bipolar cell collects signals from about how many rods?

• A. 10
• B. 15
• C. 20
• D. 30

Answer: (B)

Convergence in the rod pathway determines how many rods feed into a single rod bipolar cell, shaping light sensitivity and spatial detail. Near the fovea, there are relatively few rods, so each rod bipolar cell pools input from about 15 rods. This moderate convergence provides enough signal in low light without sacrificing too much spatial resolution in that region. As you move toward the peripheral retina, more rods converge onto the same rod bipolar cell, increasing sensitivity at the cost of finer detail. So the best answer is that about 15 rods feed a single rod bipolar cell near the fovea.