I was taught years ago by a Poodle&Lhasa breeder to look at the tear ducts. In the front of the duct & down in the bottom eye lid lots of times there are very soft refine hair. We all know what it feels like when a hair gets in our eyeballs! OK... These little hairs pull out very easily! I was amazed how much this helps the tearing!! I check all the groomers I do that have runny eyes and they usually have a few slimmy hairs in there! The dogs in general don't mind when I quickly pull the hair out. It's as if they enjoy getting that off the eyeball.
What I do
is use my index finger pull the bottom eyelid by the duct like we do to
get something out of our tear duct area. You than will see little wet
hairs outside laying in the tear area. Take your fingers grab the hairs
and pull till you can't see them anymore. Like I said the hairs come out
with ease! We did this all the time to our different breeds that we
showed.Pekes,Shih Tzus,Poms Lhasas,and all the variety of Poodles. Anyway
I just automatically check my grooming dogs. Of course this doesn't cure
the problem but will help to slow the flow of tearing!!