Evolution of human colour vision lights, which appear to be clear. Other colour perception issues include having trouble distinguishing yellows from reds and violet, lavender and purple from blue. In other cases, objects that reflect both red and blue light may appear to just be blue to these individuals. Deuteranopes, who are missing medium wavelength sensitive cones, are similar to protanopes in that they cannot distinguish between colours in the green-yellow-red part of the electromagnetic spectrum. However, deuteranopes do not suffer from dimming issues. For example, purple colors are not seen as being opposite to other colours in the spectrum but instead appear to be
Human eye the curvature of the lens is carried out by the ciliary muscles surrounding the lens; this process is called "accommodation". Accommodation narrows the inner diameter of the ciliary body, which actually relaxes the fibers of the suspensory ligament attached to the periphery of the lens, and allows the lens to relax into a more convex, or globular, shape. A more convex lens refracts light more strongly and focuses divergent light rays from near objects onto the retina, allowing closer objects to be brought into better focus. The human eye contains enough complexity to warrant specialized attention and care beyond the