I Have Two Feral Foster Cats, I Rehabilitate Them For

I have two feral foster cats, I rehabilitate them for the Humane Society, and one of them has her left eye shutting closed . It looks as they are when kittens are first opening their eyes. There is a bit of swelling to the skin on the outside of the eye , but I don't see any signs of trauma. She was fine this morning. Untill I get her to the vet tomorrow, should I put an ointment that I have. It's Neomycin and Polymyxin B Sulfates?