Because shampoo is not the same as teardrops. When shampoo gets in the eyes, the eyes immediately understand that it is different. The liquid that lubricates the eye is approximately neutral in pH, and because eyeballs are such delicate and sensitive little flowers, even tiny changes in the environment upset them. They send a screaming message to the brain: “Help! There is something strange happening here.” And to get rid of strange matter, they tell the brain to produce water fast in order to wash away the irritant in the eyes.
Why do some shampoos hurt our eyes while washing our hair?
