Schnauzer eye mucus discharge

Question
My miniature schnauzer, Quito, is 3 years old and is about 1 foot tall.  He's been having this strange case of eye mucus for about a month now.  It has worsened just a little bit.  He has a red trail, that looks like a tear, coming out of the corner of his inner eye.  Any ideas with what that might be?

Answer
Your dog needs to be seen by a veterinarian or, preferably, a veterinary ophthalmologist. He could have conjunctivitis, distichiasis, fungal infection, bacterial infection, corneal dystrophy, uveitis, dry eye, allergies, or one of a few other things. The "red trail" is staining due to the eye drainage, and is caused by the pH of his body.