Sudden stinging, tearing and redness of the eyes are likely to be caused by acute dacryocystitis. Eye infections, including Staphylococcus aureus and Streptococcus haemolyticus, are common due to a decrease in eye resistance caused by factors such as overuse of the eyes. In children, Haemophilus influenzae infection may also be the cause of this condition. Stinging and tearing eyes caused by keratitis are usually accompanied by photophobia and loss of vision.