I don;t know how come nobody replied so far, and I do hope something has
been done about this by now, but if I was you, I'd have the eye checked with
the vet, especially if it has been running all the time. It could a
conjuctivitis, which would probably turn into a colored white or yellow
discharge eventually and will require drops. "Normal cold" unfortunately is
very dangerous in cats and is cold cat flue. It is often a deadly desease
and should be treated asap. Running eyes and strong conjuctivitis are often
first symptoms. Please check the cat with the vet.
Good luck

Gee