Final answer:
Vision is clearest when an image is focused on the fovea of the retina, thanks to its high density of cones and unique structure that minimizes light absorption by non-photoreceptor cells.
Step-by-step explanation:
Given adequate light, vision is clearest when an image is focused on the fovea of the retina. This region is located at the center back of the eye and is responsible for acute vision, thanks to its high density of cones. Unlike other parts of the retina, the fovea lacks supporting cells and blood vessels, which allows for the least amount of light absorption by non-photoreceptor structures, resulting in the highest visual acuity. The unique anatomy of the fovea, with each photoreceptor connected to a single retinal ganglion cell (RGC), provides sharp visual transduction without the need to integrate multiple inputs, as is the case toward the edges of the retina.