tear

Tears are a complex fluid produced by the tear duct and glands that lubricate and protect the eye. The tear film has three layers: an inner mucous layer, a middle lacrimal secretion layer, and an outer lipid layer. This film prevents the eye's surface from drying, provides nutrients and oxygen, and has antibacterial properties. Tears are secreted by accessory lacrimal glands, with reflex tearing stimulated by irritation, bright lights, or emotions, originating from the main lacrimal glands. Tears drain through ducts into the lacrimal sac and then into the nasal cavity. A decrease in tear secretion can lead to chronic dry eye, potentially threatening vision. Tears contain lysozyme, an enzyme with bactericidal action.12