What is the primary function of rod cells in the retina?

The primary function of rod cells in the retina is indeed focused on low-light vision. Rod cells are photoreceptor cells that are highly sensitive to light, allowing them to function effectively in dim lighting conditions. They do not detect color, which distinguishes them from cone cells that are responsible for color vision. Rods are also less effective at distinguishing fine details compared to cones, which are crucial for sharp vision and detail perception.

In low-light environments, rods accumulate a pigment called rhodopsin that enables them to detect even small amounts of light. This ability makes them essential for night vision or for vision in dark environments. As a result, when light levels decrease, the activity of rod cells increases, allowing us to perceive our surroundings despite the lack of bright light.

The other options relate to functions that involve the cone cells or other aspects of vision that are not primarily managed by rod cells. Color vision and detail vision rely on the presence and functionality of cone cells, which are abundant in well-lit conditions. Depth perception involves the integration of visual information from both eyes and the processing of that information in the brain, rather than being specifically tied to the function of rod cells.