Final answer:
Color-blind individuals do not have more rod cells; instead, they have a malfunction in cone cells. Rod cells can be studied in low light conditions where they are the primary active photoreceptors, allowing for isolation of rod function.
Step-by-step explanation:
The question concerns the photoreceptor cells in the human retina, specifically the rod cells and how their number or functioning might differ in color-blind individuals compared to people with normal color vision. Color-blindness is generally related to deficiencies in cone cells, not an increase in rod cells. To study the function of rods, experiments should be performed in low-light conditions, where cones are less active, to understand rod functionality better. Interestingly, there are about 120 million rods in the human retina and they are responsible for peripheral vision and detecting motion, especially in dim light, but they do not provide color information. When in a very dark environment, even people with normal vision will notice a loss of color perception, yet they can still see gradations of light to dark (grey scales).
Considering the function of rods and cones, a useful experiment might involve individuals transitioning from a brightly-lit environment to a dark one, to observe how quickly they adapt and start seeing shapes more clearly. When returning to bright light, it usually takes a few minutes for the eyes to adjust again. This is due to the time it takes for the rods and cones to adapt to the different lighting conditions, a process known as 'dark adaptation' and 'light adaptation' respectively. To specifically focus on rods, one should consider conducting studies in near-darkness or at threshold-light levels where cones do not respond, thus isolating rod activity.
In terms of visual acuity, the fovea is the part of the retina where vision is the sharpest as it contains a high density of cones and is the point of central focus. Any assessment of the detail in the visual perception should compare the sizes of these photoreceptors to the sizes of objects, like print text, being observed.