This is a blockage of the tear drainage pathway that connects the eye to the nose. Tears are produced in the eyelids and cover the eye like a waterfall. Because of gravity, tears eventually form a small “lake” running along the edge of the lower eyelid. This lake drains through little holes in the eyelid called puncta, through some “underground tubing” in the skin and eventually into the nose. This drainage pathway is called the nasolacrimal system, and is the reason when we have runny eyes, we tend to have a runny nose as well. If this pathway becomes blocked, the tears have nowhere to drain, instead welling up in the eye and even running down the cheek. In adults, nasolacrimal duct (NLD) obstruction can be temporary if from allergic soft tissue swelling or permanent if caused by scarring from a prior infection. Many children are born with a temporary NLD obstruction at birth that eventually resolves during the first year (but may also require probing to manually force open). In adults, NLD obstruction often requires a surgical procedure called a dacryocystorhinostomy (DCR for short). This surgery involves making a small incision on the skin and creating a new drainage pathway for the tears to enter the nose. This type of procedure is usually performed by an oculoplastic surgeon, though occasionally ENT doctors will perform the same procedure.