Final answer:
The sharpest vision is achieved when the image of an object is focused on the fovea, the area of the retina with the densest concentration of photoreceptor cells, which are responsible for acute detail and color perception.
Step-by-step explanation:
For the sharpest vision, the image of an object should be focused on the fovea. The cornea and lens of the eye work together to form a real image on the retina. The retina, a light-sensitive layer that contains photoreceptor cells, has the densest concentration of these receptors in the fovea, which is responsible for high-acuity vision. In contrast, the optic nerve creates a blind spot because it lacks photoreceptor cells, and thus images focused there would not be perceived.
The fovea contains cones, which are photoreceptors that provide the ability to perceive fine details and colors, especially in bright light. As the lens adjusts its power to accommodate objects at varying distances, the goal is to ensure that the center of the image falls on the fovea to achieve the clearest possible vision.