What does the fovea become at night?

The fovea is a small region in the retina that contains a high concentration of cone cells, which are responsible for color vision and high acuity in bright light conditions. At night, in low-light environments, the visibility is largely governed by rod cells, which are more sensitive to light but do not convey color information or detail as effectively as cones.

As light levels decrease and conditions become dimmer, vision shifts away from the fovea, which can be less effective in low light, and instead relies more on the peripheral regions of the retina where rod cells are more prevalent. This transition is why the fovea does not provide effective vision at night and results in a reduced ability to see clearly – often described as a "blind spot" in terms of high-resolution color vision capability. Hence, in the context of night vision and the functions of the retina, the statement that the fovea becomes a blind spot at night highlights the limitations of color and detail perception in low-light conditions.

The other concepts, such as being an active focal point or enhancing peripheral vision, don't accurately reflect the physiological changes that occur in vision during low-light conditions, and the fovea's specific role regarding color recognition diminishes significantly in the dark.