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.
There are no certain answer of how many colors are there in the world.Careful measurements of our visual systemâs best performance have been made by psychophysicists . They have shown that we can see about 1000 levels of light-dark, 100 levels of red-green, and 100 levels of yellow-blue for a single viewing condition in a laboratory. This means that the total number of colors we can see is about 1000 x 100 x 100 = 10,000,000 (10 million). A computer displays about 16.8 million colors to create fullcolor pictures, really more than necessary for most situations. However, the answer is not quite so simple.