Dacryo-Cysto-Rhinostomy, or DCR, is a surgical procedure that creates an artificial passage from the nasolacrimal sac into the nasopharynx. The normal passage of tears goes from the ocular surface through the canaliculi into the nasolacrimal sac, then down the nasolacrimal duct, and out into the nasopharynx. If any part of this pathway is blocked, it causes chronic, excessive watering of the eye. The most common blockage occurs in the nasolacrimal duct and DCR surgery is done to relieve this.