Hi Kiki,
My cat was just dx'd with herpes in her eyes. For years, we too, thought it was allergies, but no. According to my vet, herpes is very common in cats. The way I figured out what was possibly going on with my cat was to google "feline herpes conjunctivitis." Some sites will give you pictures to look at and compare as well as descriptions.
Discharge from the eyes have many possible dx's, but a simple blood test will confirm whether your kitty has herpes or not.