The lacrimal sac is a small, pouch-like structure located in the inner corner of the eye. It is part of the tear drainage system, which helps collect tears produced by the lacrimal glands. These tears are essential for keeping the eye moist and protecting it from irritants. When tears are produced, they flow across the surface of the eye and drain into the lacrimal sac through tiny openings called puncta. From the lacrimal sac, tears travel down the nasolacrimal duct and into the nasal cavity, helping to keep the eyes clear and comfortable.