Just an FYI. I found this site and it explains a lot. Apparently Yorkies are predisposed to dry eye. It is called KCS.
(Keratoconjunctivitis Sicca) DRY EYE IN DOGS - Chinaroad Lowchens of Australia
I have also looked at sites that explain KCS.
My vet did test Chip and did not think that Chip needed the tear stimulant just the tear replacement. He also told me that there are three "ingredients" to a dogs tears, with water being the largest and that the "gunk" is from the other two "ingredients".
I thought that the gunk was occurring due to too much tearing. Goes to show ya - I need to think less sometimes.