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Pinhole Bifocal Eyeglasses

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The DIY Pinhole Eyeglasses.
A simple, ultra low cost, do it yourself type of corrective eyeglasses, made from an aluminum soda can and capable of simultaneously correcting myopia (nearsightedness) and hyperopia (farsightedness) using the pinhole lens principle. See for free.

Vision care is an extraordinarily expensive activity. Diagnosis is a lengthy process requiring trained doctors and expensive equipment, while treatment requires custom lenses for each individual made using high precision equipment and materials. The minimum cost is ~50 USD for each eye exam, and ~100 USD for each pair of eyeglasses. For those living in regions where the average wage is 1 USD per day, it is hopeless to ever expect vision care. Anyone who has poor eyesight just has to live with poor eyesight. But it doesn't have to be that way.

Enter the DIY Pinhole Eyeglasses. Consisting of nothing more than an aluminum soda can preforated by pushpin or knife with a grid of small holes and tied on with string, it is capable of partially, but sufficiently correcting vision to read and see, near or far.

Background[edit]

Why do people need good eyesight?

  • To read books or street signs
  • To see the blackboard and get an education
  • To drive a vehicle
  • To use computers or watch television
  • Or just to see what is going on

Basically, good eyesight will be needed for several ways to escape poverty. But every current solution for good eyesight cannot be afforded by those in poverty.

Adjustable-focus eyeglasses fill a similar need as the DIY Pinhole Eyeglasses. They offer superior vision correction and image quality, and also do not require an eye exam, but are several orders of magnitude greater in cost (~30 USD each) and cannot be made locally. [1][1]

Conventional refractive prescription eyeglasses and contact lenses work, but these are so great in cost (~100 USD each) and require so much infrastructure to create and maintain, that they are infeasible as an appropriate technology. Bifocal lenses are even more expensive.

Laser eye surgery also works, but it is several orders of magnitude more expensive than even prescription eyeglasses (~5000 USD), has side effects and requires hospitals to have highly trained specialists and precision laser surgery equipment reserved for only the richest of first world countries.

Commercially available Pinhole Eyeglasses.

Pinhole Eyeglasses already exist, they are sold by several different manufacturers with the lowest costing one at 3 USD. They are primarily marketed as a homeopathic cure for poor eyesight. They do not in fact cure poor eyesight, but they will correct it while worn like perscription eyeglasses. However, low cost shipping is only available to areas with highly developed transportation infrastructure, so the real cost to those who need them is much higher than just 3 USD.

Such is why the DIY Pinhole Eyeglasses (~.05 USD) are useful. They are extremely cheap and work for all prescriptions simultaneously. They can be used as both normal eyeglasses and reading eyeglasses. They can be made by anyone, with anything, very easily and quickly. Although they are only approximately half as good at correcting vision as true refractive prescription eyeglasses, they are 1/2000 of the price, so are a reasonable entry-level substitute and backup.

As a quick test, try poking a small pinhole with a pushpin through a piece of aluminum cut from the side of an aluminum soda can, then place the pinhole close to your eye and look through the pinhole at a bright object such as the outside or a computer screen. Compare the view with and without the pinhole.

Project goals[edit]

  1. To allow people in poverty to have decent eyesight, thus able to read, learn, travel and work better.
  2. To create an emergency backup vision correction system for those who rely on prescription eyeglasses or contacts. Simply put, the movie cliche of a glasses-wearing character being doomed because they lost their glasses is obsolete.

Design[edit]

DIY Pinhole Eyeglasses

  • Corrects nearsightness, farsightness and other refractive errors of the eye.
  • Can be made from an aluminum soda can, a pin, a rock, scissors and string in one hour.
  • Can also be used as sunglasses or safety glasses.

The DIY Pinhole Eyeglasses is very simple. It is nothing more than about 150 small holes poked in a sheet of aluminum cut from an aluminum soda can. Each hole indepedently corrects a narrow portion of the field of view. The diameter of the holes determines the strength of the pinhole lens effect, which affects the clarity and dimness of the resulting image. There is a trade-off between clarity and dimness, in that the smaller the hole, the greater the clarity, but the dimmer the resulting image. The recommended diameter is .5 mm.

The spacing of the holes determines how visible the mesh is, or how much of the view is blocked. The closer the spacing, the less of the view is blocked. However, if the spacing is too close, such that the same object can be seen by one eye through two holes, then there will be a double-vision effect that results in blurriness. The optimal spacing depends on light level, as the number of holes that can be seen by an eye depends on pupil diameter, which varies between 2 mm and 8 mm. The recommended hole spacing is 5 mm.

The size of hole grid determines the maximum field of view. 43x7, or 43 holes per row and 7 rows, is the recommended grid size.

The pinholes are best if they are in a thin, flat material. It does not have to be aluminum from a soda can, but it is one of the best materials since it is cheap, thin, pierceable by pin and holds an edge well.

String is used to tie the eyeglasses to the head. Any cord type can be used. Use any knot to tie the ends of the string, such as the Butterfly bend.

The DIY Pinhole Eyeglasses is designed to be mass-producible. It is easily possible to stamp the entire eyeglasses out of sheet aluminum. It is also designed to be self-makeable without eyeglasses by anyone who needs eyeglasses. Each completed set can be used as a template to make more DIY Pinhole Eyeglasses.

What you need[edit]

Materials (these will be used up)[edit]

Image Item Purpose Tested Substitutes Untested Substitutes
Pinhole eyeglasses 1 Aluminum soda can 20cm x 8 cm rectangular piece of thin and opaque material Cloth, wood, clay
Pinhole eyeglasses 1 m of String To tie the DIY Pinhole Eyeglasses to the head Elastic straps wire, plastic bag or aluminum soda can

Tools[edit]

Image Item Purpose Tested Substitutes Untested Substitutes
Pin To create small, round holes in material Nail Sewing needle, knife, rock shard
Scissors To cut the material into the template shape Knife
Rock To grind away the burrs created by poking pinholes in aluminum as well as any sharp edges from cutting it Sandpaper or file or tile
Cardboard The supportive backing for poking holes in a material Fabric, cork, clay, sand

Optional template[edit]

Image Item Purpose Tested Substitutes Untested Substitutes
Pinhole eyeglasses Paper Pierceable material to draw a template on
Pencil or pen To draw lines on paper
Ruler To measure distance between lines
6 paperclips (optional) To attach template to material Tape

How to make[edit]

First world[edit]

1. Find an aluminum soda can. Look in recycling cans.

2. Cut out a flat rectangle of aluminum from the soda can, by cutting off the top and bottom of the can and then cutting down the side.

3. Place template on the colored side of the flat rectangle of aluminum.

4. (Optional) Attach template to aluminum with paper clips

6. Use pin to poke small holes in aluminum according to template marks.

5. Cut edges of aluminum according to template.

7. Remove template.

8. Sand burrs off the noncolored side of the flat rectangle of aluminum.

9. Test pinholes, if the image is too dark, enlarge pinholes by pushing the pin through holes deeper and then sand again.

10. Cut out string holes.

11. Add string through the holes, through the top right hole noncolored side to colored, then through the bottom right hole colored to noncolored, then through the bottom left hole noncolored to colored, then through the top left hole colored to noncolored.

12. Wash DIY Pinhole Eyeglasses before wearing. DIY Pinhole Eyeglasses are now complete. To use, place them over eyes and tie the string around the back of head using shoelace knot to secure.

13. To increase comfort of long term wearing, slightly bend the nose bridge out.

How to make DIY Pinhole Eyeglasses
ImageStep
Pinhole eyeglasses Step 1 : Find an aluminum soda can. Look in recycling cans.
Pinhole eyeglasses Step 2 : Cut out a flat rectangle of aluminum from the soda can, by cutting off the top and bottom of the can and then cutting down the side.
Pinhole eyeglasses Step 3 : Place template on the colored side of the flat rectangle of aluminum.
Pinhole eyeglasses Step 4 (Optional) : Attach template to aluminum with paper clips
Pinhole eyeglasses Step 5 : Cut edges of aluminum according to template.
Pinhole eyeglasses Step 6 : Use pin to poke small holes in aluminum according to template marks.
Pinhole eyeglasses Step 7 : Remove template.
Pinhole eyeglasses Step 8 : Sand burrs off the noncolored side of the flat rectangle of aluminum.
Pinhole eyeglasses Step 9 : Test pinholes, if the image is too dark, enlarge pinholes by pushing the pin through holes deeper and then sand again.
Pinhole eyeglasses Step 10 : Cut out string holes.
Pinhole eyeglasses Step 11 : Add string through the holes, through the top right hole noncolored side to colored, then through the bottom right hole colored to noncolored, then through the bottom left hole noncolored to colored, then through the top left hole colored to noncolored.
Pinhole eyeglasses Step 12 : Wash DIY Pinhole Eyeglasses before wearing. DIY Pinhole Eyeglasses are now complete. To use, place them over eyes and tie the string around the back of head using shoelace knot to secure.
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Third world[edit]

1. Find an aluminum soda can. They are very common as litter.

2. Sharpen nail by grinding it on a rock. Make it as pointy and cone shaped as you can.

3. Cut out a flat rectangle of aluminum from the soda can, by cutting off the top and bottom of the can and then cutting down the side.

4. (Optional) If you have paper and pencil, you can make a template for poking the holes. Draw a square grid of points by drawing two sets of parallel lines half of a pinky fingernail apart (5 mm) that intersect at a right angle.

5. (Optional) Place template on the colored side of the flat rectangle of aluminum. Keep both the template and flat rectangle together using anything that you have.

6. Use nail to poke small holes in aluminum according to template marks. If you do not have a template, poke two perpendicular lines of holes, one horizontal and one vertical, 5 mm between holes, with the horizontal line having 21 holes and the vertical 7 holes, with both lines sharing one hole. Use the resulting axes to find where to poke the remaining holes.

7. Cut edges of aluminum according to template. Remove template. If you do not have a template, just cut the corners round and cut out the nose bridge.

8. Use rock to grind the noncolored side and edges of the flat rectangle of aluminum to flatten and remove burrs.

9. Test pinholes, if the image is too dark, enlarge pinholes by pushing the pin through holes deeper and then grind again. Repeat this step until image is sufficiently bright yet still clear enough to read text.

10. Cut out string holes. Cut string holes out with knife, circle of pinholes or fold and cut.

11. Add string through the holes, through the top right hole noncolored side to colored, then through the bottom right hole colored to noncolored, then through the bottom left hole noncolored to colored, then through the top left hole colored to noncolored.

12. Wash DIY Pinhole Eyeglasses before wearing. DIY Pinhole Eyeglasses are now complete. To use, place them over eyes and tie the string around the back of head using shoelace knot to secure.

13. To increase comfort of long term wearing, slightly bend the nose bridge out.


Costs[edit]

Item Price ($) Paid ($)
Aluminum soda can $0.05 $0.00
String, 1 m $0.02 $0.00
Total $0.07 $0.00

Usage notes[edit]

  • Sweat builds up with use, causing slight fogginess as water blocks pinholes. Wetness also chafs eyelids. Remove and wipe dry as needed.
  • Do not use if there are open wounds on the eye or eyelid. The DIY Pinhole Eyeglasses will often touch the eyes with normal use, which may contaminate wounds with bacteria, if the DIY Pinhole Eyeglasses are not clean.
  • Pinhole eyeglasses have poor depth perception. This is acceptable when reading text or 2D displays. Remove them when dealing with very near objects or when complex hand-eye coordination is necessary.
  • Pinhole eyeglasses dim light like sunglasses. They can indeed be used as sunglasses, for they do reduce UV light.
  • Pinhole eyeglasses provide decent impact protection, so can be used as safety glasses.
  • If there are any tears, just make the smallest possible fold to remove the sharp corners. Also poke a small hole at the tip of the crack to stop further tearing by removing stress risers.
  • If a string hole tears, either repair the hole with tape or cut a new hole.
  • Aluminum fatigues, which means do not fold the DIY Pinhole Eyeglasses back and forth or it will break.
  • May also correct astigmatism.
  • To reduce blindspots, use wall-eyed vision while wearing the DIY Pinhole Eyeglasses. This may cause temporary headaches on removal after periods of long use.

Theory of operation[edit]

Pinholes act as ideal lenses, they form images without abberations by blocking all out of focus rays. They are commonly used in pinhole cameras as the lens.

When used with a refractive lens, the pinhole acts as an aperture stop, reducing the abberations of a non-ideal refractive lenses such as a cheap spherical lens or a nearsighted eye.

Test results[edit]

40% scaled Snellen chart, 10' distance, indoor, daytime[edit]

Subject: 5 diopters myopia
Without pinhole eyeglasses: Cannot read any lines
With pinhole eyeglasses: 20/50
Comments: 40% Snellen test should actually be performed at 8' distance.

Using computer[edit]

Subject: 5 diopters myopia
Without pinhole eyeglasses: Usable at normal viewing distance
With pinhole eyeglasses: Cannot see anything, leaning in very close to read text
Comments: This entire article was written while using DIY Pinhole Eyeglasses

Watching television[edit]

Subject: 
Without pinhole eyeglasses: Usable at normal viewing distance
With pinhole eyeglasses:
Comments:

Reading blackboard, 10m distance(?)[edit]

Subject: 
Without pinhole eyeglasses: 
With pinhole eyeglasses: 
Comments: 

Reading book, 0.5m distance(?)[edit]

Subject: 
Without pinhole eyeglasses: 
With pinhole eyeglasses: 
Comments: 

Bicycling[edit]

Subject: 
Without pinhole eyeglasses: 
With pinhole eyeglasses: 
Comments: 

Discussion[edit]

Next steps[edit]

Currently looking for volunteers to try following the How to make instructions and give feedback on its clarity.

Conclusions[edit]

References[edit]

Further reading[edit]

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

Contact details[edit]

Post on this article's Appropedia discussion page or email typ0@i2pmail.org

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