What If You Survive the Apocalypse and Only Have One Pair of Contacts?

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iStock

My biggest fear goes something like this: The apocalypse or an apocalyptic event happens. There are earthquakes, asteroids, nuclear wars—whatever, it doesn’t really matter. After the flames finally stop raining down and the world has settled into an ashen plain of sorrow I come to a startling realization: My glasses are at home and I’m wearing monthly disposable contact lenses.

I would be at a competative disadvantage should I ever have to enter "survival mode" without the aid of glasses or contacts. Even the smallest and weakest of children who happen to be blessed with normal eyesight would leap above me on the food chain. I would be susceptible to naturally occurring apocalyptic hurdles and booby traps —a comically obvious net placed on the ground could very easily be my downfall.

Assuming my glasses (as well as the home in which they were sitting) were washed away by a river or lava or something equally inconvenient, I would be reliant on the lenses hugging my eyeballs to guide me through the end of the world.

How Long Will My Contacts Last?

If properly cleaned and stored overnight, my contacts remain comfortable for about a month. Given that the apocalypse will probably be pretty dusty, I can't bank on having that much time. In order to prepare for this scenario, I spoke with Gary Heiting, OD, the Senior Editor of AllAboutVision.com. He said that, depending on the person, a pair of monthly contacts can be worn anywhere from one to three months (although three is pushing it). Wearing contacts longer than recommended greatly puts you at risk for serious eye infection.

In fact, infection is the greatest contact lens-related threat I'd face after the apocalypse. Acanthamoeba keratitis, for example, is caused by a one-celled organism that can dig its way into your corneas and eventually eat away at your vision. According to Dr. Heiting, the most likely causes of this kind of ailment are handling lenses with unclean hands or direct exposure to contaminated water.

Cleaning Contacts In The Filthy Apocalypse

I assume clean water will be tough to come by after the apocalypse (especially if I am in some sort of Waterworld-type scenario—surrounded by water but none of it is suitable for washing my hands, the cruel, cruel irony), so Purell would have to do. Dr. Heiting said that, in a pinch, antibacterial hand wash is fine, but you have to be very careful to ensure that all traces of alcohol have completely evaporated before making contact with your eyes. Still, soap and water is always the best bet.

I'll be able to loot a drugstore for saline solution (and snacks and sports drinks), so, for a couple of months, I will have good enough vision to wander the charred Earth and look for roaming bands of survivors whose trust I will undoubtedly have to earn with a series of daring deeds ("That was close..." "You're telling me!" That kind of thing).

What About Fresh, Packaged Lenses?

Even with Purell and fresh saline solution, my contacts won't last forever—soon, it will come time to find replacements. Naturally, I’m going to want to loot either A) an optometrist's office or B) a contact lens manufacturing plant (by this time I will have become very good at looting). Unfortunately, even in sealed packaging and taken directly from the assembly line, these contacts won't last for an eternity.

Contact lenses have expiration dates, and I asked Dr. Heiting how concrete those were. According to a source in the contact lens industry, manufacturers must prove that the lenses are stable up to that date (usually around three years after production). It's not like milk, in that the lenses will necessarily go bad once that time comes, but it's still a risk to wear expired contacts. Dr. Heiting said he can't recommend wearing expired contacts, "except perhaps in cases of dire emergency when the risk of very poor uncorrected vision outweighs the possibility of lens parameter changes or possible contamination."

Well well well, looks like I'm in business. A pair of factory-fresh lenses will last around three years, so I should be okay until civilization is rebuilt. When that time comes, I can visit my optometrist for a long-overdue checkup.

How To Ensure You're Never Up Apocalypse Creek Without A Paddle

Now, there are precautions one can take to ensure that they don't have to worry about their contact lenses during the apocalypse. Dr. Heiting recommends that you consider eyeglasses an "emergency medical device." Keep a pair on you at all times and you'll never have to worry. Still, having glasses isn't a 100% guarantee that the end of the world will be a breeze:

The best bet for a comfortable and crystal-clear apocalypse is LASIK or other types of refractive surgeries. Dr. Heiting says that many firefighters, police officers, and other first responders get these procedures done because they are faced with harrowing situations daily that can be made all the more difficult by cumbersome glasses or finicky contact lenses.

See you after the apocalypse—I'll be the guy dodging booby traps and reading faraway street signs with no trouble.

What's the Difference Between Cement and Concrete?

Vladimir Kokorin/iStock via Getty Images
Vladimir Kokorin/iStock via Getty Images

Picture yourself walking down a city block. The sidewalk you follow may be obscured by shuffling feet and discarded gum, but it’s clearly made from something hard, smooth, and gray. What may be less clear is the proper name for that material: Is it concrete or cement? Is there even a real difference between the two words?

Though they’re often used interchangeably, concrete and cement describe different yet related elements of the blocks, flooring, and walls that make up many everyday structures. In simple terms, concrete is the name of the gray, gritty building material used in construction, and cement is an ingredient used in concrete.

Cement is a dry powder mixture that looks much different from the wet stuff poured out of so-called cement trucks. It’s made from minerals that have been crushed up and mixed together. Exactly what kind of minerals it’s made from varies: Limestone and clay are commonly used today, but anything from seashells to volcanic ash is suitable. After the ingredients are mixed together the first time, they’re fired in a kiln at 2642°F to form strong new compounds, then cooled, crushed, and combined again.

Cement
Cement
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This mixture is useless on its own. Before it’s ready to be used in construction projects, the cement must be mixed with water and an aggregate, such as sand, to form a moldable paste. This substance is known as concrete. It fills whatever mold it’s poured into and quickly hardens into a solid, rock-like form, which is partly why it’s become the most widely-used building material on Earth.

So whether you’re etching your initials into a wet sidewalk slab, power-hosing your back patio, or admiring some Brutalist architecture, you’re dealing with concrete. But if you ever happen to be handling a chalky gray powder that hasn’t been mixed with water, cement is the correct label to use.

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Why Do You Stop Feeling Tired As Soon As You Climb Into Bed?

tommaso79/iStock via Getty Images
tommaso79/iStock via Getty Images

There are few situations more frustrating: After a day spent nodding off at your desk, on the train, and on your couch, you suddenly can't sleep the moment you crawl into bed. It's not that you aren't tired or have insomnia, necessarily. Like a curse designed just to torture you, the sleeplessness only seems to occur when you're in your own bed at home, a.k.a. the place where you'd prefer to do your sleeping.

This maddening problem isn't in your head. According to TIME, many people have more trouble falling asleep in their own beds than they do elsewhere thanks to a phenomenon called learned or conditioned arousal. Conditioned arousal develops when you inadvertently train your body to associate your bed with being awake. In many cases, this results from doing stimulating activities in bed. For instance: If you like to slip under the covers and spend 40 minutes watching Netflix before closing your eyes, you're teaching your brain that your bed isn't for sleeping. That means the next time your head hits the pillow, your body will respond by preparing for the next episode of Friends instead of releasing the chemicals that help you fall asleep. The same goes for scrolling through apps, eating, and even reading in bed.

Doing things that aren't sleeping in bed isn't the only way to develop conditioned arousal. If there are other factors keeping you up at night—like thoughts about your day, or that cup of coffee you had at 8 p.m.—they can lead to the same result. Your brain starts to associate being in bed with tossing and turning all night, so even if those mental and physical stimulants go away, the muscle memory of being awake in bed remains.

Conditioned arousal is a vicious cycle that can't be broken in one night. The only way to manage it, according to the American Psychological Association (APA), is to minimize behaviors that contribute to poor sleep habits and to reserve your bed for sleeping (though sex is OK, according to the APA).

If you're a nighttime scroller, browse apps in a different room before getting into bed, or skip checking your phone at the end of the day altogether. When you spend more than 20 minutes struggling to fall asleep in bed, get up and move to a different part of the house until you get sleepy again; this will stop your brain from strengthening the association between your bed and feeling restless. The results won't be instant, but by sticking to a new sleep routine, you should eventually train your body to follow healthier patterns.

Of course, combating conditioned arousal alone isn't always effective. In people with conditions like anxiety and insomnia, intrusive thoughts and genetic factors can prevent them from falling asleep even under ideal circumstances. In such cases, the help of a medical professional may be required to sleep more soundly.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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