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.
So, I wondered, what is the smallest size a human eye can actually see? According to a whole bunch of sources all across the internet, it's either 200-400Âµm, 100Âµm, or 58-75Âµm. I also hear 'the width of a human hair' very often, but those can range from 17 to 181Âµm.