Have you ever chopped onions and felt those stinging tears, only to ugly-cry later over a sad movie? Tears might seem like simple solutions of salt and water from your eyes, but they are far more intriguing. They are your body's Swiss Army knife, handling everything from eye care to emotional release.
How Tears Are Produced
Tears are produced by our body almost non-stop, forming an invisible layer over the eyes. However, sometimes they flood out in response to joy, pain, or even laughter. But are all tears the same? Let us break down the different types.
Three Types of Tears
Humans produce three main types of tears: basal, reflex, and emotional. Basal tears constantly coat our eyes, containing proteins like lysozyme to fight bacteria and lipids to prevent drying. Reflex tears gush out in response to irritants such as onions or smoke; they are mostly water to flush threats out of the eyes almost instantly. Emotional tears occur during strong feelings like sadness, joy, or anger and are unique to humans. They flow slower but carry stress hormones like ACTH and painkillers like enkephalin, potentially helping to dump emotional baggage. All tears exit through the same ducts, but their chemistry sets them apart.
How Tears Are Made
Tears begin in the lacrimal glands above your eyes, triggered by nerves. According to the Smithsonian, reflex tears drain out after corneal sensors detect irritants, such as onion gas vapor or tear gas. The trigeminal nerve instructs the glands to flood the eyes. Emotional tears, on the other hand, route through the limbic system, the brain's emotion hub, activating parasympathetic nerves with acetylcholine. In simpler terms, the brain uses its "rest and relax" chemical messenger to trigger calming body responses. In this case, no irritant is needed; feelings alone cause the tears. Basal tears are produced steadily by accessory glands for continuous lubrication. All tears mix water and salts, but extras vary by type.
Are Emotional Tears and Onion Tears the Same?
Onion tears are reflex tears, which are basic rinsers with high water content, low proteins, and no hormones. According to the Cleveland Eye Clinic, emotional tears contain more—around 24% higher protein—plus prolactin, ACTH for stress, and Leu-enkephalin as natural opioids. Studies by William Frey found that emotional tears relieve tension by excreting built-up stress chemicals. Even sad and joyful tears differ from each other. In 2013, American photographer Rose-Lynn Fisher used an electron microscope to capture the structure of 100 different human tears. Microscopically, dried reflex tears form spiky crystals, while emotional tears swirl with organics from hormones. Both types may sting a bit, but emotional tears also cause face flushing and sobs due to brain connections.
