Skepticism

Nerd Immunity! Do Glasses Protect You From COVID?

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Transcript:

Well, it’s been a rough year but I’m happy to report that there’s finally some good news. For me. “Glasses wearers less likely to get COVID, study says.” Oh, joy! Hooray! This is absolutely great news for me and other glasses wearers. Nerd immunity y’all! Yep, no need to continue reading past the headline! I definitely don’t need to click the link to the study, and then read it in full, and then find significant issues with it that I believe invalidate the conclusions.

Dear god why must I ruin everything?

Sigh.

Okay. So, this is not the first time we’ve heard something like this. Doctors in China last summer noticed that not many of their COVID patients wore glasses, so like good little scientists they did not trust their own biased experiences and instead looked at the data. This past September, they published their results: sure enough, out of 276 COVID patients they found that only 5.8% wore eyeglasses, compared to 31.5% of the general population. That’s a pretty big difference!

However, the authors point out that they weren’t able to make definitive recommendations based on this one study. It may be that eyeglasses lower your chance of contracting COVID, maybe because they make it so that you’re less likely to touch your eyes (after touching a surface with COVID on it) or it may be that it’s less likely for COVID particulates sneezed or coughed or breathed out by someone to land on your eyeball, where they can then travel into your nose and lungs. I mean, there’s a reason that a well-equipped medical professional who is dealing directly with a COVID patient wears goggles and/or a face shield in addition to their mask: the eyes are a definite possible entry point for nasty things to get in your body.

So it could be that, OR it could be that rich people are more likely to be able to afford glasses and they’re also more likely to be able to quarantine properly and not even be exposed to COVID. OR it could be that older people are more likely to wear glasses, and those people are also more likely to take quarantine seriously and avoid exposure to the virus.

The researchers suggested that future research follow up on those things to drill down on exactly why they got the results they got.

Well! Scientists in India heard the call and they answered with this study published this month: Risk of Corona virus disease 2019 (COVID-19) among spectacles wearing population of Northern India. And while they did find that, and I quote, “The present study showed that the risk of Covid-19 was about 2-3 times less in spectacles wearing population than the population not wearing those. The nasolacrimal duct may be a route of virus transmission from conjunctival sac to the nasopharynx,” when you actually read the study like the tremendous dork that I am you learn that they did not bother to improve upon the Chinese study at all and in fact fucked up new things.

Despite the fact that they cite the Chinese study, so they must have read it, they did not bother to control for variables like socioeconomic status. Additionally, they determined that 19% of the 304 patients they surveyed wore eyeglasses most of the time. They compared that to about 40% of the general population who wear glasses. How did they get the 40% figure? Well, they pulled it from this study published in 2019 that found that about 40% of Indians had corrected vision problems (53.1% had vision problems, and 10.2% were uncorrected…they also say ).

Unfortunately, that study does not actually tell us how many of those people with corrected vision are correcting their vision with glasses. Because contact lenses also exist, and a shit ton of people wear them! How many? Well, I have literally spent hours trying to figure that out. Percentages vary from country to country and there’s not a lot of good data. I found an article from 20 years ago suggesting that 2% of Indians wore contact lenses sometimes or always, and a study from 4 years ago suggesting that 40% of Indian medical students wear lenses — the popularity of contacts in India has exploded in the past decade or two so it makes sense that a lot more people would be using them, though I’m sure medical students would use them more often than the general population. While I can’t find an exact number, it’s clear that a significant portion of people with corrected vision are not wearing glasses and it’s bad science to assume otherwise: 19% of their COVID patients had glasses, which should not be compared to 40% in the general population but more like 25-35%. It’s still a difference, but the difference is much smaller, and considering that this study only had 42 patients who wore glasses often….that’s not quite as compelling as it used to be. “2-3x less risk” is now “anywhere from no statistical difference in risk” to “not quite 2 times less risk.”

And let’s not forget that the demographics of who wears contacts versus glasses are significantly tied to gender (women are more likely to wear contacts), age (younger people are more likely to wear contacts), and income (richer people are more likely to wear contacts). Considering that all three of those demographics are less likely to contract and/or die from COVID-19, if you control for those demographics and for contact lenses in your data and still find that glasses offer some protection, now you would finally have some actual evidence worth putting out a press release for.

Unfortunately, we have none of that. 

For the record, I don’t doubt that wearing glasses provides some tiny amount of protection. But is it enough for all of you to run out right now and cop my style? Probably not. Just stay home. Wear your mask when you go out. Be as safe as you can.

Rebecca Watson

Rebecca is a writer, speaker, YouTube personality, and unrepentant science nerd. In addition to founding and continuing to run Skepchick, she hosts Quiz-o-Tron, a monthly science-themed quiz show and podcast that pits comedians against nerds. There is an asteroid named in her honor.

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