There are several conditions that alter an individuals perception. People suffer from nearsightedness, farsightedness, poor vision, or even a rare condition called monochromats. Monochromats are individuals who only have rods and no cones. All they see is white, gray, and black. Due to this condition, these individuals suffer from blurry vision when using the center of their vision (fovea). Also, a lack of cones causes color blindness and a lack of seeing detail.
Monochromats are restricted to seeing solely from their rods, permitting good vision to low light, movement, and seeing things clearer through their peripherals. In most cases, monochromats can partially see with the center of their vision. This is because the center of ones vision relies mostly on cones, however do use some rods. These rods must work powerfully in order for monochromats to see sufficiently.
In conclusion, an average human being with usual vision will be using their rods and cones because these both play an equal role in vision. However, monochromats have to rely completely on their rods to see. This makes their vision much different that an ordinary human being. These individuals may have eccentric habits such as looking at individuals with the corner of their eye to legitimately see objects effectively. Also, they may be poor with color coordination. For example, these individuals may be poor at matching clothes due to their lack of seeing colors for what they are perceived to be ordinarily. Monochromats are a unique group of inidividuals who have an extraordinarily different conception of vision and how to most optimally see objects than a human being with ordinary vision.