@Darwin Really, now? Drawing a line between this and smoking weed? That seems pretty arbitrary. The only possible connection I can imagine is that Visine and other red-away drops can be bad for your eyes, but I’m not sure that that would affect a tear duct in any event. As far as herb itself goes, it’s is supposed to be good for the eyes in some ways – helps glaucoma by relieving pressure on the eyes, or so the NIH says. But again, I’m not sure how much this side-effect could be connected to tear flow. Can you link to some evidence for the connection you’re drawing? My google-fu isn’t turning anything up.
@Macaulay If it is a blocked tear duct (which is apparently rare in adults), it can indicate a bunch of different things. From this site: “In adults, tear ducts may become blocked as a result of a thickening of the tear duct lining, nasal or sinus problems, injuries to the bone and tissues around the eyes (such as the cheekbones), infections, or abnormal growths such as tumors.” So – go see a doctor.