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.

Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
Geoview/iStock via Getty Images

When it comes to physical activity, few animals have as maligned a reputation as the sloth. The six sloth species, which call Brazil and Panama home, move with no urgency, having seemingly adapted to an existence that allows for a life lived in slow motion. But what makes sloths so sedate? And what horrible, poop-related price must they pay in order to maintain life in the slow lane?

According to HowStuffWorks, the sloth’s limited movements are primarily the result of their diet. Residing mainly in the canopy vines of Central and South American forests, sloths dine out on leaves, fruits, and buds. With virtually no fat or protein, sloths conserve energy by taking a leisurely approach to life. On average, a sloth will climb or travel roughly 125 feet per day. On land, it takes them roughly one minute to move just one foot.

A sloth’s digestive system matches their locomotion. After munching leaves using their lips—they have no incisors—it can take up to a month for their meals to be fully digested. And a sloth's metabolic rate is 40 to 45 percent slower than most mammals' to help compensate for their low caloric intake. With so little fuel to burn, a sloth makes the most of it.

Deliberate movement shouldn’t be confused for weakness, however. Sloths can hang from branches for hours, showing off some impressive stamina. And because they spend most of their time high up in trees, they have no need for rapid movement to evade predators.

There is, however, one major downside to the sloth's leisurely lifestyle. Owing to their meager diet, they typically only have to poop once per week. Like going in a public bathroom, this can be a stressful event, as it means going to the ground and risking detection by predators—which puts their lives on the line. Worse, that slow bowel motility means they’re trying to push out nearly one-third of their body weight in feces at a time. It's something to consider the next time you feel envious of their chill lifestyle.

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

Are Any of the Scientific Instruments Left on the Moon By the Apollo Astronauts Still Functional?

Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Apollo 11 astronaut Neil Armstrong left the first footprint on the Moon on July 20, 1969.
Heritage Space/Heritage Images/Getty Images

C Stuart Hardwick:

The retroreflectors left as part of the Apollo Lunar Ranging Experiment are still fully functional, though their reflective efficiency has diminished over the years.

This deterioration is actually now delivering valuable data. The deterioration has multiple causes including micrometeorite impacts and dust deposition on the reflector surface, and chemical degradation of the mirror surface on the underside—among other things.

As technology has advanced, ground station sensitivity has been repeatedly upgraded faster than the reflectors have deteriorated. As a result, measurements have gotten better, not worse, and measurements of the degradation itself have, among other things, lent support to the idea that static electric charge gives the moon an ephemeral periodic near-surface pseudo-atmosphere of electrically levitating dust.

No other Apollo experiments on the moon remain functional. All the missions except the first included experiment packages powered by radiothermoelectric generators (RTGs), which operated until they were ordered to shut down on September 30, 1977. This was done to save money, but also because by then the RTGs could no longer power the transmitters or any instruments, and the control room used to maintain contact was needed for other purposes.

Because of fears that some problem might force Apollo 11 to abort back to orbit soon after landing, Apollo 11 deployed a simplified experiment package including a solar-powered seismometer which failed after 21 days.

This post originally appeared on Quora. Click here to view.

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