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 University Optometry, 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 University Optometry, we put your family's needs first. Talk to us about how we can help you maintain healthy vision. Call us today: 650-666-2191 or book an appointment online to see one of our Palo Alto eye doctors.
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