Basal tears are constantly produced throughout the day, and form a liquid layer over your eyeballs. Their purpose is to lubricate, nourish, and protect the eyes from particles in the air. Most humans produce five to ten ounces of basal tears per day. Basal tears drain through the nasal cavity, which explains why many people experience a runny nose after crying.
Everyone who isn’t a robot understands that humans cry and secrete tears during moments of extreme sadness, pain, or distress. When the brain experiences sadness, it sends signals to the endocrine system to release hormones to the ocular area. These hormones are what cause people to cry after experiencing emotional trauma, or after watching the ending to Million Dollar Baby.
Many scientists seem to agree that crying allows the body to release certain chemicals that build up during stress. Adrenocorticotropic hormones, which are correlated with high levels of stress, are usually found in tears secreted from emotional sadness, but are not found in tears caused by chopping an onion. The findings seems to suggest that there is such a thing as “having a good cry” to make you feel better physically and mentally.
Reflex tears are formed in response to sudden external stimulus. These stimuli can include eye irritants such as dust particles, smoke, or gases in the air. This physiological response works to quickly wash away foreign substances that have come in contact with the eye. Sensory nerves in the cornea alert the brain stem of the foreign particles, which in turn releases hormones to the lacrimal glands (the gland that produced tears). Reflex tears are chemically similar to basal tears.
Epiphora, or excessive tearing, can be classified as the surplus of tears produced by one or both eyes. Epiphora can occur continuously or intermittently, and is caused by either the overproduction of tears, or inadequate drainage of tears. Epiphora can cause leakage and an excess of water on the cornea, which may blur an individual’s vision. The condition may be made worse by harsh winds or dry climate.
If your eyes have been producing too many or too few tears, it may be necessary to schedule an appointment with your optometrist. Contact Silverstein Eye Care Centers today at (816) 358-3600 or request your appointment online. We can serve you at our convenient location in Independence/Kansas City.
Bonus — Specific types of tears have different appearances when viewed under a microscope.