I am not a Vet but it's so common. My previous yorkie had this as does my current baby. The vet will probably want to make sure it is not an ingrown hair or blocked tear duct. My vet recommended I use Baush & Lomb Opcon-A for allergy itchy eyes (yes, people eye drops)....one drop in each eye 2x a day when needed. For really goopy days like spring and fall when the pollen is flying around he gave me Neopolydex Opthal. Suspension one drop 2x a day only when she looks really runny. I also gently clean her eyes once a day with a little water on a tissue and dry it as well as I can. Good luck and always check with your vet first...