Unless you are going to show him it probably isn't worth it. How old is he, have you had his tear ducts checked for blockages? That could be part of your problem. Otherwise I have hear Eye Envy works well. I don't have a breed with tearing problems. It is something you would have to do every day, maybe even several times a day.
yes, you can check for problems, but it's pretty normal. If it's bothering you, make sure you are feeding a good, high quality food, natural,(I feed Innova), and you can wipe them with a little diluted hydrogen peroxide (the one most of us keep around) on a cotton ball. Make sure you don't get this IN the eye . It helps with the enzymes a little, like it does with blood. Also cheaper and more effective than alot of the store products.If you get her hair cut, you can also ask your groomer to do a cleaner scoop (they can try a blade shorter than the 10 there), but it might irritate the skin the first few times, just like anything that close they're not used to.
Also wanted to add since we are talking about a shih-tzu, one of the problems you may want to look into if it is excessive during your next exam is distichia (eyelash issues). Could just be normal tearing though. http://www.animaleyecare.net/diseases/canine.htm