Tårflödet

Tårflödet, medically known as lacrimation, refers to the production and flow of tears from the lacrimal glands. Tears are essential for maintaining the health and function of the eye. They lubricate the ocular surface, preventing dryness and irritation. Tears also contain antibodies and enzymes that help protect the eye from infection and foreign particles.

The process of tear production involves the main lacrimal gland, located above the outer corner of each eye, and smaller accessory glands within the eyelids. Tears are continuously produced in a basal amount to keep the eye moist. However, tear production can increase significantly in response to emotional stimuli, such as sadness or joy, and in response to irritants, such as dust, smoke, or a foreign object. This increased tearing is known as reflex tearing.

The tears spread across the surface of the eye with each blink, forming a thin film. This tear film has three layers: an outer lipid layer that prevents evaporation, a middle aqueous layer that provides moisture and nutrients, and an inner mucin layer that helps the aqueous layer adhere to the cornea. Excess tears are drained through the puncta, small openings in the inner corners of the eyelids, which lead to the lacrimal sac and then down into the nasal cavity. This is why crying often results in a runny nose.

Disruptions in tårflödet can lead to various eye conditions. Insufficient tear production, known as dry eye syndrome, can cause discomfort, blurred vision, and increased susceptibility to infection. Conversely, excessive tearing, or epiphora, can be caused by overproduction of tears or impaired drainage, leading to watery eyes and potential skin irritation around the eyes.