I didn't look at the other thread, but an eye doctor can tell you if you have a problem with your eyes actually producing enough tears. If that is the case, then there are a couple of things they can do including plugging the lower tear ducts (not painful) to keep the tears in your eyes, or there is a prescription eye drop called Restasis (expensive if you don't have insurance) that helps your eyes produce tears (in very non-medical terminology.)

I have tried both. The plugs helped, but I could never keep the things in. I would inevitably rub my eyes too hard, and next thing I knew they weren't in there anymore.

The Restasis drops have helped a lot. I used to have to keep a bottle of drops with me at all times, but now I rarely use drops at all. They have a rewards program that helps with the cost of the co-pay and sends you freebies every so many prescriptions - a bottle of drops once and a $20 Target gift card recently.