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 Professional VisionCare, 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 Professional VisionCare, we put your family’s needs first. Talk to us about how we can help you maintain healthy vision. Call us today: 614-898-9989 or book an appointment online to see one of our Lewis Center eye doctors.

Want to Learn More? Read on!

Frequently Asked Questions with Dr. Carole Burns

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.