Explain cats and herpes?

my cat gets a regular red (conjunctiva) weepy eye infection, sometimes green, usually clear discharge. she is a rescued barn cat. treatment with atb ung helps, but it takes q 6hr tx for at least a week. how do we know if it's herpes, and can i grind lysine in an unused coffee grinder and give her some powder on her wet food every day-- if so, how much?