I know there's already a forum for sore and tender scalps but naturally, I can't find it! I needed to register before posting...so it's GONE. For about a year my scalp has been so sore and so tender that it hurts 24 hrs a day. At first I thought perhaps I was allergic to my shampoo so I changed brands. No improvement. Next I wondered if my shower was too hot.
Although small in size, the eye is a very complex organ. The eye is approximately 1 inch (2.54 cm) wide, 1 inch deep and 0.9 inches (2.3 cm) tall. The tough, outermost layer of the eye is called the sclera. It maintains the shape of the eye.
Computing the f-number of the human eye involves computing the physical aperture and focal length of the eye. The pupil can be as large as 6â7 mm wide open, which translates into the maximum physical aperture. The f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark.