Introduction: Post Apocalyptic Prescription Glasses (Updated)

Picture of Post Apocalyptic Prescription Glasses (Updated)

So you're out in the wilderness, or downtown for that matter, and the unthinkable happens. Your glasses get destroyed, lost, or otherwise rendered unusable. What are you to do, surely you can't survive and thrive without being able to see clearly?

Fortunately for those of us with eyes that don't work correctly, there is a solution. By exploiting some simple(ish) physics we can get our vision back.

This works no matter what your prescription is, and can come in really handy day to day, or during a camping trip/survival situation.

Want to know how?

Using this exact same processes (with one minor adjustment) you can also make Glacier Goggles(really powerful sun glasses), which help prevent snow blindness and have been used by aboriginal peoples living in norther climates. I have made notes in the instructable for how to change these "glasses" into glacier goggles; these are indicated with italicized text.

//Edit Pilgrimm has some knowledgeable comments about the glacier glasses down in the comments section. //I'm thinking he(I assumed if I'm wrong please correct me) has more experience with them then I do. Head to the //bottom of the article and check them out.

//Another edit the first person who posts a "I made it" comment will get a free 3 month membership

Step 1: The Trick

Picture of The Trick

So here is how to do it without any tools, or really any effort.

Wrap your index finger in a tight circle. Keep it there with your thumb, and get your other fingers out of the way. You want to get about 1mm(diameter) opening that lets light through.

Next close one eye, and holding you hand close to your open eye, look through this little aperture created by your finger.

You should be able to see everything (no matter the distance) in focus now.

//Edit:Tallwood2000 has suggested a method to use a pencil or pen instead of your fingers to make it easier look a //little less silly :) See the comments section for their description. Wobbler also has a neat trick that is easier on the //hands. Check them both out in the comments section.

Wow, how does that work?

Step 2: The Physics

Picture of The Physics

So how can we replicate the intense machining that goes into creating modern optics with our index finger?

The truth is that we can't.

To understand what is going on we have to start with how our eyes work. All of our eyes, unless something terrible has happened, have a natural lens (a piece of tissue that is more dense than air but still transparent) that bends light into the back of our eye (retina). Now lenses can only focus light that comes from a specific distance; this is why pictures are out of focus when an object is too close to the camera. Now for our natural lenses, the lens in our eye is soft and can have its shape changed by muscles in the eye. This allows us to focus on things that are close to us, and things that are far away. Unless, of course, our natural lens isn't the proper shape. This makes everything blurry no matter how hard our eye muscles try to get things in focus.

So we have invented corrective lenses (glasses) that sit in front of our eyes and bend light in a way to counteract the irregularities that our natural lens has. Now our eyes can focus the light coming at them onto our retina, then our brain does its magic and we can see.

Now obviously you can't make a lens out of nothing just by bending your finger, unless you're a wizard/witch. So what are we doing?

The reason a lens can't focus objects from multiple distances is because it takes all the rays of light and bends them into a single point. This means that if those rays are coming from further away or closer than the focal length of the lens they won't converge at a single point. Instead, they'll be spread out in a shape larger than the object, resulting in a big, blurry, object-shaped smudge.

So what if we take all the rays coming in from different directions and get rid of them and just use one? We now no longer need to take a bunch of rays and converge them onto a single point. Instead, we just let that single ray hit anywhere on the lens and it will look like the object. This is what we are doing by making that really small hole with our finger, blocking all of those extra rays which need focusing and only letting "one ray" per object through. This allows us to see, in focus, what is around us despite our natural lenses being warped.

If it is this easy to correct blurry vision why did we go to all the trouble of making lenses in the first place?

As well as this simple trick works, there are some problems. You'll notice quite quickly that everything is significantly darker when you are looking through that little hole. Remember all those extra rays that we are blocking out? By blocking all of those we are drastically reducing the amount of light that reaches our retina, making everything darker. It is this that we exploit to make glacier goggles. You'll also notice that all depth perception is gone. It becomes really hard to tell how far away something is, especially if you don't know the size of the object already. So that is why corrective lenses are better, but they are way more difficult to make.

Now this is a really simplified explanation of what is really happening, because light isn't a ray, it's a wave, or particle, or both. But I will leave higher level physics classes to explain that to you, because I would probably not do that good a job.

Step 3: Materials You'll Need

Picture of Materials You'll Need

As this is a survival project some of these following steps won't apply if you are making these in the field, but it should help as a reference.

Materials and Tools that You'll Need:

A piece of leather: Roughly the same size as your glasses (Mine is scrap from another project, but if you are out in the bush, a leather belt will work really well for this. Depending on your eyes and your belt you might be able to get away with using the section of belt that is perforated instead of punching your own holes)

A Knife: It will need to have a fairly small point on it to make the holes.

String or Twine: Or another method for attaching the "glasses" to your face.

Cutting Surface: I used a cutting board but anything you can cut the leather on will work.

That is all you'll need.

However if you want to make these look good...

A Measuring Device: This is to make everything symmetrical and square.

Leather dye: Add some colour (yes, I'm Canadian) to your leather, or make it look aged.

Eyelets: The holes last longer and not stretch out.

(If you are using eyelets you will also need: An eyelet punch and "anvil" (these usually come with the eyelets but not always), and a rubber or wooden mallet)

Step 4: Designing the Glasses

Picture of Designing the Glasses

Start with a piece of paper, and using the knife poke some different sized holes in it. Experiment to find the largest hole that lets you focus, this will let in the most light and make these more functional.

Next you need to measure the distance between your eyes, I did this experimentally, but you can measure the distance between the center of your glass' lenses (this should also be on your prescription, should you have it handy). I poked a bunch of small holes in a piece of paper and determined which two fit the distance between my eyes. Remember that when you make this out of leather it is going to curve over your nose and take that into account when determining the distance between pupils.

//Edit:Pilgrimm has mentioned that using a slit instead of a hole will alleviate the need for this step, and allow //multiple users to use these "glasses". It will be more difficult to cut out of the leather though.

Now its time to figure out how big we need our piece of leather to be. Measure your existing glasses, or guesstimate by placing your hand across your face and measure the distance between your fingers. Same for the height of the band.

Once you have the rough dimensions they can be transferred to the leather.

Pencil works well, or you can lightly cut the marks in with the knife.

Edit// Based on the comments I have received I have updated the design of the "glasses". They now feature two slits //above and below the first pin hole, and another pin hole on the ear side of the first. These changes allow for greater //peripheral vision, without compromising the ability to focus.

Step 5: Cut Out the Leather

Picture of Cut Out the Leather

Once you have the marks on the leather you can begin to cut the piece out.

I used a leftover bit of a scrap piece I bought at Tandy Leather Supply. It is 5oz. vegetable tanned shoulder, I believe. The whole piece cost $23.99 (as evident in the photo) but the other project used the majority of it up.

Use the pocket knife and the ruler to cut out the leather in straight lines.

Once the leather is cut out, it's time to make the holes for the strap to go through.

On the edges of the short side, where the arms of your glasses would be, mark a place for a hole the same diameter as your string.

To make these holes you could use a leather punch; however it can be done quite easily with a pocket knife. Using the knife as a drill, rotate the cutting edge around in a circle. I put in two holes big enough for the eyelets that I am using.

// EditWobbler and michaellb2 have raised a good point, if you want to you can put in more holes. This will increase // your peripheral vision and allow more light in. There are actual glasses like this: link. Just be careful not to put them // too close together.

Next, if you have them, it's time to put in the eyelets. The eyelets will stop the cord from stretching the holes in the leather, they also add a professional look to the project. If you don't have them the "glasses" will still work just as well, so don't worry.

I put eyelets in with a screwdriver, rubber mallet, and the little "anvil" that came with the eyelet set. Starting with the screwdriver and a #4 Philips bit I punch twice per eyelet, rotating by 45 degrees each time, to bend over the edge. Then I use the spreading tool and the rubber mallet to more evenly bend over the edge. With this project the smooth side of the eyelets should face inwards towards you so that the bent over side doesn't scratch you.

Step 6: Wet Forming

Picture of Wet Forming

In order to make these "glasses" contour to your face, and to block out more light, it helps to wet form the leather.

To do this dunk the leather in a bucket of warm water, let it sit for about 30 seconds so that it becomes pliable. Then place it against your face and mold it around your nose and the sides of your face. Make sure you have enough space your your eyes to open and close without your eyelashes getting in the way.

Make sure that the leather touches you face all the way around your eye socket so that no light gets in.

Leave it on your face for 3-5 minutes until the leather stops losing its shape when you take it off. When it maintains its shape you can take it off and let it dry, this will take a while.

Once it is dry you can dye it if you wish.

Step 7: Adding the Apertures

Picture of Adding the Apertures

Now that you have your "glasses" formed to your face its time to make the apertures that will let you focus. Using the paper template from earlier, mark where the holes should be. Next, being very careful, use the knife to make little holes the same size as you did on the paper.

Make slits (~10mm x ~3mm) that you can see comfortably out of, but remember the bigger the opening the brighter and less effective they will be.

Step 8: Adding the Band

Picture of Adding the Band

The wet forming will help the "glasses" fit your face, but in order to ensure that they stay there we are going to add a band.

To let the "glasses" be adjustable I tied one piece of twine to each of the two larger holes we put in earlier. I then tied the two pieces together using a system of knots that can slide but are also reasonably secure, called a clove hitch (see how to tie one here , we're using another piece of string rather than a wooden bar). Doing this twice, once for each side of the head, allows the knots to slide until they hit each other, making the "glasses" easy to tighten and loosen.

Alternatively you could just tie a length that is the same size as your head between the glasses.

Step 9: Final Remarks

Picture of Final Remarks

Now you have a set of "glasses" that you can make, should your normal prescription ones get damaged. A useful skill to know if you, like me, depend on your prescription glasses to see the world clearly. Now as we have already discussed they have some limitations, which is why we had real glasses before.

These are not a replacement for corrective lenses. I will not be held accountable for anything that happens to you or that you do while wearing these. I do not recommend using these unless you really are SOL and desperately need to be able to see clearly.

I added dye and some tooling patterns to the "glasses" once they where done. I didn't show these in the steps because I didn't think it was necessary. I will however be writing another ible' soon which covers how to do that.

There are a few limitations while using these:

  • The main one is the limited range of vision, reducing what you can see to two pinpricks can be quite dangerous, especially in our modern world.// This is reduced greatly by adding more apertures.
  • The darkness caused by blocking out the majority of the light that enters your eyes.// Also reduced with more //apertures
  • The loss of depth perception; this makes moving around while wearing them quite disorientating.//Still an issue

However, there are moments where you need to be able to focus:

  • Being able to read would be the largest one: if you are on a trail and lose your glasses, reading the map for directions would be key to helping you survive.
  • If you need to start a fire, being able to see fine detail (like for making a featherstick) would be a great help.
  • Performing first-aid- even cleaning out a little cut is really hard if it's a big red blur.

I would use these only when I need to clarify something. Don't wear them all the time while you're walking around; I have, it's awful.

Hope you learned a new useful trick, but also that you never have to use it. If you liked this instructable please give it a vote by clicking the trophy in the top right corner. If you have any questions, please post a comment, or pm me. Thanks for reading- Lucas

Comments

bcavaciuti (author)2015-10-30

Awesome instrucible :D another application is for shooting, though possibly a separate sight apparatus would be more appropriate, then you could get a more accurate hole for one eye more easily!

nic.bryan.73 (author)bcavaciuti2017-06-13

For shooting I personally would only put a hole in the shooting eye, use the other side as an outright blindfold.

tutls (author)2016-02-20

I discovered this method when I was around 8 yrs old. It hasn't been working lately anymore, I don't know why.

905kat (author)2015-11-15

Holy crap! I took your idea and just looked at my computer screen to see quickly if it would work and it did! Next time I'm in the car and have a map or are in a restaurant and have forgotten my glasses I'll use this trick! Thanks so much! In the mean time, I'll start on working on my vision. I can't believe this works! Thanks again.

Zaphod Beetlebrox (author)905kat2015-11-16

You are welcome glad it will come in handy.

CarlaS25 (author)2015-11-14

Thank you. That is nice to know.

Zaphod Beetlebrox (author)2015-11-03

Thank you very much to everyone who voted for me.

nodeal (author)2015-11-03

I discovered this at they eye doctor's once when I had my eyes dilated. By making a very small circle with my finger (like an 'OK' sign), I was able to peer through this and read text on a magazine page.

rundmcarlson (author)2015-10-15

Not to dump on this because it is very neat, but a more practical solution rests in the pockets of nearly everyone these days: a cameraphone. If you have a phone capable of taking photos, you can look at the live camera view and you only have to be able to see the phone screen to see literally any focal distance. This only works for nearsighted people obviously.

bcavaciuti (author)rundmcarlson2015-10-30

"Post Apocalyptic" means you don't get phone chargers after the apocalypse sorry about that. But its fine for normal life, though I actually find it more convenient to use the finger hole method!

rundmcarlson (author)bcavaciuti2015-10-31

I can make my entire house run on solar and batteries in a few hours. I 100% will have a phone charger lol

bzurn (author)rundmcarlson2015-10-25

Wow. I just tried that with the camera phone and it works really well. I am very nearsighted, -7.25.

Unfortunately I'm a plus 6 and a +6.5 not particularly near sighted ;) but yes it will work if you can focus on your phone, and that your phone has power. Thanks for sharing.

Kshatrya (author)2015-10-25

Good idea!

Thanks

RockyG (author)2015-10-25

*than

Ward_Nox (author)2015-10-25

so i'll be able to see AND it will freak ppl out cause it looks liek i'm blindfolded...win win

Ward_Nox (author)Ward_Nox2015-10-25

...though you should put some hols on the sides so light can get in that way you'll have some periferal vision

I did after the update, there as also slits above and below the main aperture.

tyler roberts (author)2015-10-24

this should help with snow and sand blindness too.

Yup, that's what the glacier goggles where originally used for.

askjerry (author)2015-10-18

I need glasses to read... sometimes I forget them... then I had a problem. I did something similar a long time ago... since I do electronics... I have several small drill bits... I took a 0.05 inch and a 0.07 inch (1.27 and 1.778 mm respectively) bits and drilled a couple of holes into a plastic ID card. This is always in my wallet... so in a pinch, I can use it to see.

That's a good idea, thanks for sharing.

KittyF (author)2015-10-18

I need glasses to see anything clearly past 5-5.5 inches from my eyes. this method, (only tested with my hand as you first suggest) extends my abilitys to around 14 inches. possibly helpful, but won't help me shot an intruder or save myself from walking off a cliff. LOL good for those with better vision though, I'm sure.

elmarco88 (author)2015-10-09

Wouldn't the reduction of peripherals as well as the remainder of your vision be counterintuitive to a post apocalyptic or survival situation?

gstephens1 (author)elmarco882015-10-17

Given the option of being completely blind or being able to see without peripheral vision, I think the best option is the ability to see.

Having been camping and lost my glasses in the river, I can tell you that the rest of the activities of being in the wilderness are made more difficult. But, you don't need perfect vision all the time. I can still recognize people, find trails and identify hazards without my glasses, and even better after a few hours for my eyes to adjust. But when I need to see something more clearly, the peripheral vision is not as relevant. Of course, in the woods I just used a piece of paper, some duct tape and a pencil to make the little holes.

Based on the other comments it appears that this can be remedied by adding more pin holes.

I wasn't thinking about wearing them all the time, just for when the ability to focus is more important than peripheral vision.

Lozchik (author)2015-10-17

Awhile back, my husband bought some pinhole glasses. They made you look like a fly when you wore them ;P I guess he gave up on trying to make a pair from scratch. They were interesting to use, but even those were still rather dark for my taste. I guess they would have been good for sunny days. I'll have to try it if I can frind them.

owatson (author)2015-10-16

These give you a large depth of field like a pinhole camera. This will let you focus on very close objects (3-4cm away) so you can probably use these "glasses" as a primitive microscope even if you are not short sighted.

owatson (author)owatson2015-10-16

You might even be able to see separate pixels on some computer screens

Cool, I didn't notice it but I wasn't really looking for it.

Nana2Peanut (author)2015-10-16

Great 'ible!

As one who is profoundly nearsighted, I have always worried about how I could survive after an apocalypse - now, I know.

Printers also use the "curled index finger" trick to focus in on small areas of the printed sheet when checking color or registration - blocking out the distractions. I wish they would all just put on one of your masks . . . . .

makemesomecookies (author)2015-10-16

Thank you! I just always assumed that I would die pretty quickly after an apocalypse due to my horrible vision, but now I can survive a bit longer!

Great job and I voted for you!

Thank you.

thundrepance (author)2015-10-15

i like how you molded the leather! i wonder if i could make a decent sleep mask out of leather, using your method. i've had over 10 sleep masks of different materials. not a single one keeps the light out! x^(

It's pretty dark inside, and if you have a thinner piece (4oz) I think you could get a closer fit, cause there are a couple of places where it lifts of my face.

NKhaliqsharif (author)2015-10-16

Hye ! atlast you did it ! worth doing indeed !

NKhaliqsharif (author)2015-10-16

Hye ! atlast you did it ! worth doing indeed !

tallwood2000 (author)2015-10-15

I occasionally forget my glasses and need to read something. I use a pen or pencil, held close to my eye, and get clear focus down the edge of the pen. No fatigue from a curled finger. Looks a little weird in a restaurant when I'm reading the menu...

wpace (author)tallwood20002015-10-15

I have used the pin hole technique all my life, but I just tried your
pencil technique for reading and it works very well and it's easier to do.
Thanks!

Zaphod Beetlebrox (author)wpace2015-10-15

I could see that it was getting clearer but I couldn't get a clear focus. My prescription is pretty high though, I can see it working for some people.

kenobi (author)tallwood20002015-10-15

Tried the pencil method, didn't work for me. Maybe due to my astigmatism.

Pinhole method, or opening between fingers does work for me

ariachus (author)2015-10-11

This is actually based on the wave properties of light. This is the same as how you can sometimes hear the loudness of music coming from two speakers increase or decrease based on where your head is, constructive and destructive wave interference. Also I work at an eyeglasses making store and the distance between eyes, as this guy calls it, is referred to in your prescription eyeglasses as the Distance Between Lenses (DBL), typically between 14mm and 19mm, plus your Left and Right Pupilliary Distances (PD), typically between 25-35mm. On your eyeglasses, if it hasn't worn off from wearing, the there will be three numbers separated by dashes and the middle one is the DBL eg 10-16-24 or two numbers on the bridge and its typically the first, this is notably much smaller on some frame styles like aviators in which its often in the single digits. So if you have your eyeglasses prescription you can do this much more exactly.

finchts (author)ariachus2015-10-15

..not really. While you can't really separate out any of the properties of light from contributing to the situation, this is definitely more of a ray optics problem/solution than a wave optics. The author explained it pretty well, this works because you're limiting aperture based aberrations. Counter-intuitively, you're actually getting worse diffraction because of this, it's just that the decrease in aberration content is enough to offset that.

As I said it's a really simplified explanation. Thanks for both of your inputs, Maybe I'll add some more to that step...

Thanks that's good to know, I'll quote that in the instructable if that is okay with you?

wobbler (author)2015-10-15

I use the pinhole trick, but I do it by putting thefirst two fingers next to eackother and then putting the tips onto the thumb. There's a little triangle formed in the middle which you look through with your fingers about 6cm in front of one eye.

There are also reading glasses made which use a grid of pinholes instead of lenses. You can find details of how they work here:

https://en.m.wikipedia.org/wiki/Pinhole_glasses

I've also seen sunglasses like the pinhole glasses which often have a screen printed logo or image on them.

However, your design is much cooler!

Pilgrimm (author)2015-10-15

Terrific 'Ible! Excellent explanation of the physics involved! I've been wearing corrective lenses for a very long time, and while I've heard of pin-hole cameras, never have I seen a clear explanation of why it works. FYI The Inuit, Tlingit and other far northern native peoples often make glacier/snow goggles using similar methods, but use a very thin slit in lieu of small pin-hole apertures. This eliminates the necessity of finding your personal "pupillary distance", reducing eyestrain, allows a bit more light, and I believe, helps with depth perception. It also permits more than one person to use the same set of goggles. I've seen Inuit sighting a rifle while wearing their snow goggles! Great 'Ible! Good Luck - Cheers.

michaelb2 (author)2015-10-15

You can also use multiple tiny holes that will allow a wider field of vision

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Bio: Second year engineering student studying at the Beautiful Okanagan campus of The University of British Columbia. I like to tinker with electronics and meddeling with ... More »
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