My 2 year olds left eye is teary and creating lots of eye "boogers" . what could this be?

Conjunctivitis: This is caused by a virus (more common) or a bacterial infection. It is sometimes difficult to distinguish between the two. An infection that causes a mucopurulent discharge (= eye boogers) is usually more associated with a bacterial than viral cause. To be on the safe side, many choose to treat. Eye drops containing antibiotics is the treatment of choice (you will need to get these from a doctor).