Eyejusters - self-adjustable glasses designed for the developing world


May 30, 2012

The Eyejusters adjustable glasses with the adjustment tool in place

The Eyejusters adjustable glasses with the adjustment tool in place

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Anyone who currently wears glasses or contact lenses will have likely consulted an optometrist to determine their prescription ... that is, if they live in the developed world. In developing nations, many people aren't afforded the opportunity to see a professional in this field. Thankfully there are alternatives, one of which are the self-adjustable glasses from Eyejusters.

The British company is aiming to take low-cost, self-adjustable glasses to developing nations. In order to do so, the team of four have developed an adjustable lens technology called SlideLens. This consists of a pair of lenses which act together to correct an individual's eyesight. By sliding one of the lenses over the other from left to right, the prescription changes until the world comes into focus.

There are two different types of SlideLens - positive power (for long-sightedness) and negative power (for short-sightedness). The range of the positive power lenses is from +4.5 to 0 diopters, while the range of the negative power lenses is from 0 to -5.0 diopters. This covers the majority of common cases. The glasses are priced at US$39.95 for the individual buyer, but the main aim is to distribute these to people in the developing world.

A pair of Eyejusters glasses being worn in Malawi

No professionals are required in the process of distribution, with anyone who has received basic training able to get involved. After a simple reading test, the type of glasses required by each individual patient is determined. They then choose which color they want, and can adjust the lenses until they're happy. A repeated reading test ensures an overall improvement in the patient's eyesight. The whole process can be seen in the video embedded at the bottom of the page.

Alternative Solutions

These aren't the first self-adjustable glasses ever conceived, with the Adaptive Eyecare spectacles developed by Professor Joshua Silver already on the market. Previous attempts have used fluid-filled lenses to solve the problem, but I personally feel turning a screw to adjust the prescription is a more elegant solution than spectacles adjusted using syringes and tubes. The Eyejusters also look less cumbersome and more stylish, although they wouldn't be many people's first choice of frames. This is function over form, and they do the job they need to do.

Regardless of the method used, this is definitely a problem in need of a solution. There are estimated to be 670 million people around the world living without the glasses they need, with 95 percent of the people in sub-Saharan Africa who need them going without. This is due to there being an average of one optometrist per one million people in that part of the world, compared to one per 10,000 in the United States and Europe ... which is a frankly shocking statistic.

Source: Eyejusters via RedFerret

About the Author
Dave Parrack Dave is a technology journalist with a ravenous appetite for gadgets, gizmos, and gubbins. He's based in the U.K., and from his center of operations writes about all facets of modern and future technology. He has learned more in his five years writing for the Web than he did in 11 years at school, and with none of the boring subjects thrown in to the mix. All articles by Dave Parrack

Fantastic idea but I couldn't help but think of the Optigrab device from The Jerk.


It would be fairly simple to integrate an unobtrusive slider and eliminate the screw, solving the aesthetics dilemma.


Heavy frames with adhesive tape move over; there's new geek glasses in town!

Shawn Corey

Per Thier FAQ: "... Recent research has also shown that individuals with low-to-moderate levels of astigmatism can also achieve a good improvement in their vision after performing self-refraction with adjustable glasses. However individuals with high levels of astigmatism still require custom-made prescription lenses. ..."

So, not for everyone. Astigmatism is not too hard to check. A pattern of, uniform width, evenly spaced (all angles between lines the same angle, like every 10 or 15 degrees) lines through a point could be looked at. If all lines are uniformly sharp - then no astigmatism. If corrected for near or far sightedness which these glasses do, and lines along one particular direction are much fuzzier than lines of other directions then you have astigmatism, which varies in severity and direction from person to person.

Great fun to drag the lens in the web page illustration though.

If you are over 40 and don't wear glasses for astigmatism, I think these would be great: pass cursor over "Where to Buy" may be USA only at this time. Then "click her to buy" - $40. Diopter strengths range from 0 to 4.5x Adjustment dials are removable and can be re-attached Bah: "Adjustable Readers - Due to the popularity of this item, it is temporarily out of stock. Expected to ship within 6 weeks." Also you can enter email address for updates on "adjustable reader" or "developing world". GREAT WEB PAGE IMO.

Dave B13

At $39.95, they're more pricey than regular reading glasses that you can get at the pharmacy.

Victor Engel

At $40, these will be a life changer for a lot of people. Good for them.

Thomas Roberts

Victor, my guess is that you don't wear glasses. Reading glasses are not regular glasses. I am near-sighted. Reading glasses don't do a thing for that. I can't pickup a set of specs without getting a doctor's visit and a prescription.

Reading glasses are all + numbers. Near-sighted prescriptions are all - numbers.

Personally, I don't see why there aren't booths for emergency specs. Walk in the booth. Dial the lenses until they focus for you, and the 3D printer makes you a set. Pay the cashier.


My vision changes during the day, don't know why (nor do docs) so I would love these.

Fred Borman

Cheap reading glasses are the same in both eyes. Many people, like me, have different prescriptions for each eye. I just ordered a pair, waiting 6 weeks...

Fred Borman

@ Victor E., You are absolutely correct. The benefit of these is that they are adjustable, and they adjust for each eye. The pharmacy reading glasses are fixed strengths and they are fixed at the same diopter for both eyes. I have too much astigmatism for non-prescription reading glasses including the eyejusters. The strongest clip-on reading glasses I've come across as commonly available are 3.0x. These: Are may favorite of all the hood magnifiers, comes with second flop down lens inside and external loop can me moved to dominant eye, providing several strengths. You need to be closer to what you are looking at with increasing strengths of simple lenses. Also they are cheaper than drugstore reading glasses. Don't bother with the included lights, remove them.

Dave B13

Victor, there aren't the professionals available to ensure people get the right prescriptions though. So it's either adjustable lenses or send every prescription over until they find they right one. Which isn't at all practical.

Dave Parrack


There's no "aesthetics dilemma." The knob is part of an adjustment tool. Once properly adjusted, the tool is removed, which also protects the lenses from being accidentally moved.


They're better looking than the any shape you want as long as it's tiny and round Superfocus glasses.

Gregg Eshelman

I want the hawkeye from legend of zelda.


There is an additional benefit and business model change possible here in that once the wearer finds the best fit those numbers can then be used to mailorder glasses in a wide range of styles and at a price the 3rd world can afford. In one step the style, access, and cost challenges can be reduced to an achievable level. Still, in a part of the world where $40.00 is close to an annual income the 1st world will need to help.


@ Dave 13

The dial is going to break, changing it to a metal screw flush with the frame would be better.

Could not the dial also have the current neg & pos diopter set in the dial so a set of fixed diopter glasses could me made from a prescription based on the reading. The likelyhood is that those glasses are cheap, ones from locally sourced materials in Africa are cheaper still.

Currently glasses are sold on the internet & across the counter for £5 or less in the UK. The average income in Malawi in 2005 was $160 a year ( one pair of these glasses would be as much as the poorest could afford in a year, yet a pair of fixed diopter mass produced glasses costs 5 times less than the $39.95 quoted.


I had been eagerly waiting a couple weeks since I ordered these for $40 and I just got my Eyejusters. It is definitely cool to be able to adjust them and I got them for working at my electronics workbench where you are working between arms length and then real close up soldering or assembling small stuff with a need to repeatedly adjust between those extremes. I have not really tried a long session of that yet. But the clear field of view is noticeably narrow compared to the readers that I have been using for working at computer or for reading. The Eyejusters have a sweet spot with about 30 degrees field of view horizontally that is pretty sharp in the center and then going further off axis, more and more distortion and defocus sets in. Vertically I see ~20 degrees field of view before noticeable distortion.. This is with a setting of ~ +2. With my 30" (diagonal) 2500x1600 high res monitor at ~30" viewing distance the edges (last 3-4 inches on each side) are unreadable. It will be a cool item to wear (with knobs attached!) to a geek events like robotics competitons. Hopefully they can improve these, but knowing what I know about optics, I am not going to hold my breath. I can see the value in distributing these to kids in 3rd world countries with no other option but I wonder if the adjustable glasses from Superfocus or from Pixeloptics have solved the field of view and clarity issue.

Frank N

Just as a postscript for folks finding this discussion through a current search:

To Frank N's question about whether Superfocus and/or PixelOptics emPower! addressed the field of view/clarity issues - yes, pretty much. Both had pretty high-grade optics, unlike these "toy" adjustables, justifying (to an extent) their premium prices. Sadly, both companies are now out of business, and their products are no longer available. That's where the similarities end, though.

PixelOptics' emPower! eyeglasses provided an expensive and ultimately unreliable solution to a very specific problem of limited value, by eliminating the distraction of having that "reading power" zone at the bottom of your eyeglasses all the time when you weren't using it (particularly noticeable going down stairs). Starting with a mild Progressive Add Lens or PAL (providing distance and mid-range vision with little to no side-to-side distortion), emPower! then laminated an LCD layer to a zone at the bottom of the lens that added "reading power" magnification when power was applied to the LCD. The zone could be toggled on and off in a couple of different ways, either by touching a control area on the temple or by tipping the head up (to turn off) and down (to turn on); the latter "automatic" feature could be enabled or disabled through the temple touch control. The intent of the design was that you could have full-powered reading glasses when you wanted them, but then just "turn them off" and have a user-friendly PAL for walking around without the annoying "read window" at the bottom of your field of view.

Cost aside (well over $1000), there were two main problems with emPower! First, PixelOptics grossly misrepresented the functionality of the product in their advertising, referring to them as "adjustable" and/or "electronically focused", and touting their ability to "focus near, far, and in between." Technically these statements were true at least in part, but the misleading implication was that the eyeglasses' electronics provided a focusing mechanism that could be tuned to whatever distance was desired, which was certainly not the case. The electronically controlled add region was either ON or OFF - there were no intermediate or adjustable settings. The "near, far, and in between" claim was true only to the extent that the base lens was itself a mild PAL, so with more add power at the bottom of the lens than at the top, providing a continuous range of focus options from full-distance to midrange. If you needed to see anything closer, you needed to toggle on the read-power LCD. I never tried the glasses myself, so I don't know if the PAL provided a noticeable range of add power within the reader zone itself, but it couldn't have been much given the low total add power of the base lens.

More seriously, emPower! had major reliability and durability problems. The first generation of the product suffered from widespread "delamination" of the LCD layer from the main lens, creating lines and distortions within the visual field nearly as bad as the reading area of a bifocal lens (so what was the point?). Worse, the electronics were not well protected, and many emPower! frames failed when exposed to perspiration from their wearers (bit of a problem, that - if you want to see, don't sweat). Overall, PixelOptics badly overpromised and underdelivered.

By contrast, the less glamorous (and far less expensive) Superfocus product delivered truly extraordinary functionality with somewhat flawed technology. Eschewing fancy electronics and complex layered lenses, Superfocus used a much simpler dual lens system, with a presription-ground lens up front backed by a fluid-filled lens that could be mechanically adjusted by the wearer on the fly to precisely dial in the desired add power. The main catch was form factor - because the curvature of the lens was governed by applying fluid pressure, the shape had to be perfectly circular, and to keep the lenses from getting too thick (and therefore having to move too much fluid), the size had to be fairly small. The result was Superfocus's rather distinctive Harry Potter look, and how you felt about it probably had a lot to do with how they looked on you personally. In return for this uncompromising style, though, you got a lens that did exactly what it promised - with a push of a slider or turn of a knob (depending on the particular style), you could precisely adjust focus to the exact distance needed for a given task.

The technical flaw in the first generation Icon series product was that the eyeglass temples were mounted directly to the focus module, with the prescription lenses individually mounted with magnets at the front. This subjected the focus module to torques and stresses that damaged the seals and allowed fluid to leak, ruining the focus module and requiring that the entire frame be replaced. The second generation Leonardo series reversed this design, putting the prescription lenses in a fairly conventional frame with the focus module "floating" on a magnetic mount behind the frame, and these proved to be much more durable. Another problem with the optical fluid was that it could become cloudy at low temperatures, a problem for some reason reported more often in the Leonardo series. Unfortunately, Superfocus was unable to bring in enough business to fund development of improved technology, so closed its doors in early 2014.

Adjustable lenses may return to the market if AdLens, makers of a lower-tech fluid-filled eyeglass design targeting customers in developing economies, makes good on delivering their promised Focuss or CustomFocuss series. An advantage of their design is that the adjustable region of the lens does not have to be perfectly round, allowing for more conventional styling. They were supposed to bring those to the U.S. through selected LensCrafters stores in the first half of 2014, but haven't showed up yet. One would have to assume they're having product issues that have delayed the launch.

Ule Amra
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