Psoriasis can affect the nails and produces a variety of changes in the appearance of finger and toe nails. Nail psoriasis occurs in 40â45% of people with psoriasis affecting the skin and has a lifetime incidence of 80â90% in those with psoriatic arthritis.
Color & Vision Matters. The human eye can see 7,000,000 colors. Some of these are eyesores. Certain colors and color relationships can be eye irritants, cause headaches, and wreak havoc with human vision. Other colors and color combinations are soothing. Consequently, the appropriate use of color can maximize productivity, minimize visual fatigue, and relax the whole body.
This article is about the colour. For other uses, see Blue (disambiguation). Blue is the colour between violet and green on the optical spectrum of visible light. Human eyes perceive blue when observing light with a wavelength between 450 and 495 nanometres, which is between 45 and 49.5 ÃngstrÃ¶ms. Blues with a higher frequency and thus a shorter wavelength gradually look more violet, while those with a lower frequency and a longer wavelength gradually appear more green.