Anything that seems out of the ordinary with your cat's eyes warrants a trip to the vet. Eye problems can be infectious, and can cause blindness.
Having said that, it sounds like a "kitty cold". Is it mucous-like discharge? If it is, then you can get a triple-antibiotic ointment from your vet and some internal antibiotics to clear it up. If it's anything else, it will require a closer look by the vet.
Hope this helps!