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In order to slow the spread of the new coronavirus, the Centers for Disease Control and Prevention now recommends that all Americans wear face coverings in public. If you wear glasses, you may have noticed that covering your face is causing your lenses to fog up. We've gotten to the bottom of why that happens and how you can wear your face mask or covering so that it won't happen.
Why do my glasses fog when I wear a face mask?The science behind why our glasses fog when we wear a mask is fairly simple. As we wear our masks, warm breath escapes from the top of the mask and lands on the cooler lenses of our glasses. When that happens, it creates condensation, or fog. You might've noticed a similar effect when wearing glasses with a scarf or baclava in the winter, or when opening a hot oven door.
So how do I prevent my glasses from fogging when I wear a mask?The good news is that this problem is not new, and doctors and surgeons have found several ways to prevent foggy glasses. We've consulted Dr. Jason Brinton, a leading St. Louis-based ophthalmologist and founder of Brinton Vision, on the best ways to keep your glasses clear.
- Improve the fit of your mask. Many medical masks feature a bendable metal strip that allows the wearer to mold the mask to their nose and cheeks. But you don't need a surgical mask to achieve a good fit. If you're making a homemade mask, Dr. Brinton recommends sewing a pipe cleaner or twist tie into the top of your mask. That way, you'll be able to fit the mask to your face more effectively. You'll also want to adjust your mask's straps or ear loops. When the mask fits properly, most of your breath should go through it, not out the top or sides. (Here are step-by-step instructions for wearing a face mask properly.)
- Tape your mask. Dr. Brinton says most doctors use tape to prevent foggy glasses while they work. To DIY it, tape your mask across the bridge of your nose and across your cheeks. You can use most any type of tape, be it adhesive, medical, or athletic, just make sure you avoid duct tape. Test the tape on a different part of your body to ensure it doesn't irritate your skin.
- Pull your mask up. A simple way to decrease the amount of fog on your specs is to pull your mask higher on your face and use the weight of your glasses on top of the mask to block the flow of air. "Whether or not this works will depend on the shape and makeup of the glasses," says Dr. Brinton. He says this method is most effective with large, thick frames.
- Use a commercial anti-fog wipe or spray. "These can be very effective," says Dr. Brinton. "They can also be very expensive." Right now, a box of Foggies Anti-Fog Towelettes on Amazon costs $48 for a pack of 48. Keep in mind that anti-fog solutions may not work as well on glasses with certain coatings, such as anti-glare, anti-fingerprint, or anti-smudge, and so it's important to read the fine print on each product.
Will putting soap or shaving cream on my glasses prevent them from fogging?As more people struggle with foggy glasses, several home remedies have made the rounds, including treating glasses with soapy water, shaving cream, baby shampoo, or toothpaste. These solutions may have some merit. A 2011 paper published by one British surgeon showed that washing glasses with soapy water and letting them air dry can help prevent fogginess. That's because the soap acts as a surface active agent, or surfactant, and leaves behind a thin film that helps prevents fog.
"There isn't any really good data and there aren't any really good studies on these techniques," says Dr. Brinton, "but any substance that will leave a surfactant on there that will impede the condensation can be useful."
He says that while substances like shaving cream, soap, baby shampoo, and toothpaste can all accomplish this, they aren't widely used — mostly likely because they don't last too long and aren't as effective as other methods.