Evolution of human colour vision that are found between 450 and 625. Individuals with various forms of colour blindness such as deuteranopia and protanopia are missing human middle wavelength sensitive or long wavelength sensitive opsins. Their minimum wavelength differences are <5 but only at around 500. Protanopes, who are missing long wavelength sensitive cones, are unable to distinguish between colours in the green-yellow-red section of the electromagnetic spectrum. They find yellow, red and orange colours to have much lower brightness when compared to a trichromat. The dimming of these colours can result in confusion in many cases, such as when attempting to identify red traffic
Eye-ring white eye-rings may consequently express vigorous health. In addition they may signal membership of a particular group or population, as different species and populations may have rings of differing colour, size, shape or completeness. These recognition signals could then play a role in reproductive isolation and speciation. Eye-ring The eye-ring of a bird is a ring of tiny feathers that surrounds the orbital ring, a ring of bare skin immediately surrounding a bird's eye. The eye-ring is often decorative, and its colour may contrast with adjoining plumage. The ring of feathers is sometimes incomplete, forming an eye arc. In the