Tears are produced mainly by the lacrimal gland which sits in the outer corner of the upper eyelids. Tears lubricate the surface of the eye and contain antibacterial properties. Having washed over the surface lining of the eye the tears drain away into the nose. There is a “plug hole” (punctum) in the inner corner of both the upper and lower eyelids. These are connected to narrow tubes called canaliculi which enter a small pouch called the lacrimal sac. From here the tears drain down a longer, wider tube known as the naso-lacrimal duct into the nose.