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Why Do Onions Make Us Cry?

Onions are one of the most common staple foods around the globe. Ironically, for a vegetable so delicious, they can often be tear-jerkers.

Read on to learn why onions cause your eyes to tear and sting, and what you can do to minimize discomfort.

Why Does Cutting Onions Cause Tearing?

Onions produce a sulfur compound called propyl sulfoxide that is stored in the cells of the onion bulb (the part of the onion we eat). Onions grow underground, where they can be eaten by all types of creatures. This odorous sulfuric compound acts as a deterrent to small animals with big appetites.

When one slices into an onion and breaks open its cells, the sulfur compound is released and mixes with the moisture in the air — turning it into smelly and irritating sulfuric acid. When this chemical rises up and comes in contact with your eyes, it stings!

To keep your eyes from potentially being damaged from this chemical exposure, your brain triggers your eyes to tear and flush out the irritating gas particles. Once enough tears have flushed out the sulfuric acids particles from the eye, clear vision and comfort is usually restored. Although your eyes may sting and feel unpleasant, symptoms are temporary and the sulfuric acid won’t damage your eyes.

How Can I Reduce Eye Discomfort When Chopping Onions?

Most experienced chefs will tell you that chilling your onions in the fridge for at least 30 minutes before slicing them will reduce the amount of tearing they cause. Propyl sulfoxide escapes slower in cooler temperatures, reducing the amount of sulfuric acid in the air.

You can also try cutting the onions at arm’s length, or direct the odorous air away with a small fan. Some say that chopping onions immersed in water also helps. Another option is to wear kitchen goggles to protect your eyes.

Furthermore, try to use fresh onions whenever possible. The longer an onion has been stored, the more likely it will induce tearing and discomfort. Try to avoid slicing near the root end of the bulb, as that area has the highest concentration of sulfuric compounds.

Still Having Eye Problems Out of the Kitchen?

If you frequently suffer from eye irritation — and not just while cutting onions — we can help. At Washington Eye Doctors, we treat a wide range of eye conditions and can provide you with the treatment and relief you seek.

For further questions or to schedule an eye exam, call us today.

At Washington Eye Doctors, we put your family’s needs first. Talk to us about how we can help you maintain healthy vision. Call us today: 202-335-5032 or book an appointment online to see one of our Washington, D.C. eye doctors.

Want to Learn More? Read on!

Frequently Asked Questions with Dr. Michael Rosenblatt

Q: What exactly is glaucoma?

  • A: Glaucoma is a condition in which the eye’s intraocular pressure (IOP) is too high. This means that your eye has too much aqueous humor in it, either because it produced too much, or because it’s not draining properly. Other symptoms are optic nerve damage and vision loss. Glaucoma is a silent disease that robs the patient of their peripheral vision. Early detection is very important.

Q: What’s the difference between vision insurance and eye insurance?

  • A: Vision insurance” really isn’t insurance, but rather a benefit that covers some of your costs for eyewear and eye care. It is meant to be used for “routine” care when you aren’t having a problem but want to be sure everything is OK, like having an annual screening exam with your Primary Care Physician. It often, but not always, includes a discount or allowance toward glasses or contact lenses. It is usually a supplemental policy to your medical health insurance. Medical health insurance covers, and must be used when an eye health issue exists. This includes pink eye, eye allergies, glaucoma, floaters, cataracts, diabetes, headaches, and many other conditions. Blurry vision is covered medically if it relates to a medical condition, for example the development of a cataract. For some reason, however, it is considered non-medical if the only finding is the need for glasses or a change of prescription. Of course you can’t know this until you have the exam. In this case, with vision coverage, you would only be responsible for your co-pay, but with medical coverage without vision coverage, you’d be responsible for the usual charge.

Q: How does high blood pressure affect vision?

  • A: If the blood pressure is very high it can be called malignant hypertension and cause swelling of the macula and acute loss of vision. Otherwise hypertension can cause progressive constriction of the arterioles in the eye and other findings. Usually high blood pressure alone will not affect vision much, however hypertension is a known risk factor in the onset and/or progression of other eye disease such as glaucoma, diabetic retinopathy, and macular degeneration as well as blocked veins and arteries in the retina or nerve of the eye that can severely affect vision.

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REFERENCES

https://www.britannica.com/story/why-do-onions-make-you-cry

https://theconversation.com/why-do-onions-make-you-cry-129519

The Power of Tears

tearsTears literally enable us to see. They lubricate our eyeballs and eyelids, thus preventing our eyes from dehydrating. They also provide a smooth surface for refracting light, supply oxygen, and are a vital component of the ocular defense system that protects against a range of pathogens. Below we’ll delve into the composition and types of tears, and further explain why they are so beneficial to our physical and emotional well-being.

Structure of Tears

Tears are made up of three layers: lipids, aqueous and mucous.

The lipid layer is the outermost layer and prevents the evaporation of tears. The lipids are produced by tiny glands in the eyelids called the meibomian glands.

The aqueous layer, which is the middle layer, makes up 95% of our tears. This layer supplies nutrients to the cornea, prevents infection, and heals ocular damage. This layer is effectively made up of water and is produced by the lacrimal gland.

The mucous layer is the one closest to the eye. It coats the cornea and provides a level platform that allows for an even distribution of the tear film over the eye. This layer is produced by even smaller glands called goblet cells.

The Three Types of Tears

Tears are composed of water, salts, amino acids, antibodies and lysozymes (antibacterial enzymes). However, there are several types of tears, and their composition varies. For example, the tears we shed while crying are different from the tears that flood our eyes in the presence of irritants like onions, dust or allergies.

Humans produce the following three kinds of tears:

  1. Basal – these tears are constantly at the front of the eyeball and form the liquid layer over the eyeball to keep it lubricated.
  1. Reflex – these tears appear when the eye is irritated, such as when the eyes feel gritty or when we get dust, sand or other small foreign objects in our eyes.
  1. Psychogenic – these tears are sparked by emotion. They possess a higher protein level than basal and reflex tears, which makes them thicker, causing them to stream more slowly. Psychogenic tears are made up of higher concentrations of stress hormones such as adrenocorticotropic hormone and leucine enkephalin (a natural painkiller). This suggests that emotional tears play an important role in balancing stress hormone levels.

Tears Serve the Following Functions

Prevent dryness
Tears prevent dryness by lubricating the surface of the eye. Each time we blink we spread this cushioning layer of tears across the front of the eyes.

Supply oxygen and nutrients
Oxygen and nutrients are delivered to the cornea through our tears.

Prevent infection
Not only do tears wash away foreign bodies that enter the eye, but they can also prevent infection thanks to an antibacterial property contained within tears called lysozyme. This antibacterial agent fights off the germs we pick up in our surroundings.

Heal ocular damage
Tears are made up of substances that heal damage to the surface of the eye. Damage can be caused by foreign objects and even high exposure to UV rays.

Create a smooth surface on the eye
Tears lubricate and smooth our eye’s surface, leading light to be correctly focused and enabling us to see clearly.

Remove Toxins
Emotional tears contain more toxic byproducts than reflex tears (caused by irritation), and can thus flush out many toxins and stress hormones.

Dull pain and improve mood
Crying for extended periods of time releases oxytocin and endorphins. These feel-good hormones can help diminish both physical and emotional pain. Once the endorphins are released, your body may enter a more relaxed stage, with oxytocin providing you with a sense of calm and well-being.

As you can see, tears are invaluable for clear vision, protecting your eyes, flushing out irritants, and soothing emotions.

If you feel that your eyes are not as comfortable or your vision is not as clear as usual, contact Dr. Michael Rosenblatt at Washington Eye Doctors in Washington, D.C. today.