Tearlessness occurs when the lacrimal glands are not developed congenitally, or due to an acquired autoimmune system disorder that disrupts lacrimal secretion, resulting in the desire to cry without tears. Tearlessness is an eye disease that cannot be cured, and patients can only rely on medicated ointments to improve symptoms or use special moisturizing glasses to avoid water evaporation. It is caused by chronic inflammation affecting the muscular nerves of the lacrimal ducts, which reduces the contraction of the ducts, and inflammatory infiltration around the ducts, which weakens the duct walls, and inflammatory stimulation that increases tear secretion, causing passive dilation of the ducts and the formation of cysts. Congenital lack of tears is seen in Riley-Day syndrome (familial autonomic abnormality), which is characterized by tearlessness and corneal perceptual deficits in keratoconjunctivitis, and although the patient may be asymptomatic initially, it eventually develops into a typical sensory keratoconjunctival fever. Acquired atelectasis can be caused by an auditory neuroma or surgery on the pontine peduncle of the cerebellum that destroys the lacrimal secretory nerve. Tumors or inflammation of the lacrimal gland itself can also reduce tear production.