Eli5: how come tears don’t sting our eyes even though they are salty?

Question

Eli5: how come tears don’t sting our eyes even though they are salty?

In: 1

Answer 1

Salt stings because of osmotic pressure. Water moves out of your eye cells to balance the salt concentrations inside/outside.

Tears have the same concentration of salt as the inside of your cells so that does not happen. It’s also why lubricating eye drops containing saline don’t sting either.