The production and discharge pathway of tears

Tears are also called tears. They often flow when we are sad, excited or other emotional. Many people do not particularly understand the production and discharge of tears. The lacrimal glands will secrete tears, which are then secreted through a series of pathways. There are many factors that affect the secretion of tears. Let us now understand the production and discharge of tears.

Tear production and drainage

The lacrimal gland secretes tears - lacrimal puncta - lacrimal canaliculi - lacrimal sac - nasolacrimal duct - inferior nasal meatus.

Aqueous humor circulation: aqueous humor produced by the ciliary body - posterior chamber - pupil - anterior chamber - anterior chamber angle - scleral canal sinus - ophthalmic vein.

Factors affecting tear secretion

The surface of a normal person's eye is covered with a tear film, which is composed of three layers: the surface layer is the lipid layer secreted by the meibomian glands, the middle layer is the serous layer secreted by the lacrimal glands and accessory lacrimal glands, and the inner layer is the mucus layer secreted by goblet cells and the like. A normal and stable tear film is the basis for maintaining the normal structure and function of the ocular surface epithelium. Any damaging factors that destroy the integrity and function of the tear film will cause discomfort symptoms.

Gender, MT use time, wearing soft contact lenses, and blinking frequency have statistically significant effects on tear secretion. Female, long-term MT use, wearing soft contact lenses, and low blinking frequency are risk factors for abnormal tear secretion in college students. . This is mainly because sex hormones have an important influence on tear secretion. Androgens regulate the morphology, physiology and immunity of the lacrimal glands, and can regulate the meibomian glands to secrete oil into the tear film. Low androgen levels are an important cause of abnormal tear secretion in women.

The number of mobile terminals has no effect on the tear secretion of college students, but the use time of mobile terminals has an effect on the tear secretion of college students. Some studies have shown that people who frequently use computers are prone to abnormal tear secretion, and the longer they use computers, the higher the incidence of abnormal tear secretion. This may be because under normal circumstances, human tears will continue to evaporate and be absorbed at a certain rate, and the lacrimal glands will continue to secrete a certain amount of new tears to replenish them in order to maintain the health, comfort and infection resistance of the ocular surface; but during the MT operation, because the eyes are highly focused on the video screen, the distribution of tears and enzymes is abnormal, resulting in tear secretion dysfunction and shortened tear film rupture time.

It is recommended that college students reduce their exposure time to MT, ensure adequate eye-screen distance, and take regular breaks. Continuous wearing of soft corneal contact lenses can cause decreased tear film function and corneal epithelial damage, and the longer the lenses are worn, the greater the damage.