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. An intraocular pressure check can be done in the clinic. Non-contact IOP measurement method: After turning on the instrument, adjust the position of the subject’s head so that the cornea is located in the viewing area of the observation lens, and move the positioning point to the center of the clearly focused circle, so that the subject looks at the positioning point, the instrument will automatically complete the measurement. Note: 1, before the formal measurement in order to avoid the nervousness of the examinees, should first explain to them the measurement principle of the instrument. 2, the examination is asked to open both eyes, such as eyelids blocking the results of the ophthalmometer does not come out. 3, measurement process such as position movement or excessive tears will affect the measurement results, should try to avoid.