My name is***** and I am sorry to hear that your dog has an eye infection. When I am seeing a dog with eye problems there are several tests that I want to run first to make my diagnosis.
1) Schirmer Tear Test- this evaluates tear production. Any eye problem will not heal if there is not good tear production.
2) Corneal Stain- this evaluates the integrity of the cornea and look for ulcers
3) Cytology of the mucus in the eye- this looks for infection, possible fungal organisms or other inflammatory cells.
After I have all of these answers, I would then decide on medications to address all problems present. I would also place an e-collar on the pet to prevent them from damaging their eyes.
If, after a prolonged treatment, I would be worried that there is something much more complicated. I would consider taking Muffin to a veterinary ophthalmologist for further evaluation. You can find one near you at acvo.org.
Best regards, ***** ***** this answer helps you.
Kansas State University,
College of Veterinary Medicine Class of 2001