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.
Although the human eye can distinguish up to a few hundred hues, when those pure spectral colours are mixed together or diluted with white light, the number of distinguishable chromaticities can be quite high. In very low light levels, vision is scotopic: light is detected by rod cells of the retina.