Josh Silver remembers the first time he helped someone, not only see, but regain their place in the world:
Henry Adjei-Mensah, a tailor in Ghana, could no longer see well enough to thread the needle of his sewing machine. He was too poor to afford glasses or an optometrist. Then Silver, an atomic physicist who also taught optics at Oxford University, handed him a pair of self-adjusting glasses he had designed, and suddenly the tailor’s world came into crystal-clear focus.
It is estimated that well over one billion people worldwide suffer from poor eyesight. In the United States, 60-70% of people also need glasses, but they can afford them. However, billions of other people can not afford traditionally crafted custom eyeglasses – even if they could receive the attention of an eye doctor.
One might ponder that glasses could be manufactured very cheaply – true; however, everyone needs a custom prescription, there is no “one-size fits all” approach that works with our eyes. This introduces another huge problem because there are not enough optometrists available in many of the regions with the greatest need like India, and throughout Africa. For instance, typically in developed nations one optometrist might serve up to 10,000 people; however, in say sub-Saharan Africa there is one optometrist per 1,000,000 people.
DIY: Low-cost self-adjustable eye glasses that let anyone make their own windows to the world.
Professor Josh Silver, physicist and professor of optics at Oxford University, came up with just such a solution, Adspecs, version 1.0 pictured above. Adspecs allow a user to change the power of the lens – simply turn the wheels on the syringe to change the level of silicone oil in the lenses.
The lenses, are actually two flexible membranes, protected by a hard plastic shell, and by changing the amount of oil (flex of the inner lenses) the power of the lens changes. So anyone can simply adjust the glasses until they see clearly, screw down the lock nut, and cut off the syringes.
Learn more about this revolutionary eyeglass design at the Centre for Vision in the Developing World, which since 2009 has distributed over 30,000 pairs of Adspecs. However, that is but a small dent in the over one billion who live on less than $1.00/day and have poor eyesight.
The Marvelous Human Eye:
The human eye is the original adjustable lens as our eye lens is changed (flexed) by our ring muscles (the ciliary muscle) which allows the eye lens to flatten or bulge changing the refractive power.
Common Eye Problems:
Presbyopia: A loss of ability to change the power of the lens due to hardening of the lens tissues, leading to a lack of ability to focus on close objects, such as when reading.
Myopia: (short-sightedness) Rays of light from a distant object are focused in front of the retina. Myopia occurs either because the eye is too long or the refractive elements (the cornea and crystalline lens) too powerful to produce a clear image at the retina.
Hyperopia: (long-sightedness) Rays of light from a distant object are focused behind the retina, either because the eye is too short or because the refractive elements of the eye are not powerful enough to bring an image into focus at the retina.
Astigmatism: Astigmatism occurs when the curvature of any given refractive element of the eye differs across its surface (i.e. the lens in the eye is shaped more like a rugby ball than a football). This lack in uniformity across the surfaces of the eye’s refracting elements prevents it from producing a sharply focused image at the retina. Astigmatism usually produces an image that is more defocused in one direction than another.
How Fluid Filled Lens Technology Works:
As one can see in the image above, as the level of liquid changes between the flexible lenses, their shape changes because of the incompressibility of liquids. The change of the lens alters the refractive power (how much light is focused).
Child ViSion, a new initiative between Dow Corning Corporation and the Centre for Vision in the Developing World (CVDW), have developed the next generation of self-adjusting eyeglasses specifically targeted at children, age 12-18. Perhaps you are a fellow wearer of eye glasses and remember the frustration in school of not being able to see the school board – just imagine your life, your world, if that blurriness had continued for the rest of your life?
While the Adspecs were developed for use by adults, Child ViSion eyeglasses were specifically developed for ease of use, attractiveness, and ruggedness to withstand childhood. It is obviously very important that a child can see during their school years to avoid falling behind their peers unnecessarily due to eyesight issues. How can these eyeglasses really help children?
The Story Continues:
The Child ViSion initiative can always use help with research, distribution, and partnerships.
As with any inspirational design innovation iteration brings alternatives:
Each SlideLens is a pair of lenses with a special shape that you are able to see if you hold the lens on its side and reflect light from the surface. When these lenses are slid across each other (left-to-right), their combined shapes act as if they were one lens with a changing spherical surface. The advantages of using sliding adjustable plastic lenses are easy to see – durability, reliability, aesthetics and low cost. SlideLens beats existing liquid-filled adjustable lens technology by allowing us to create durable, simple self-adjustable glasses that are as close as possible to normal glasses, boosting long-term uptake and acceptance.
Eyejusters has also created some slick packaging and distribution materials to help deliver them to the developing world. However, these glasses could certainly be great for you or someone else in your world that would just like to be able to quickly adjust their readers, for around $40.00USD.
Of course, we are a style and design blog, which brings us to the next entrant for adjustable eyeglasses, brought to us by California:
The SuperFocus lens employs a similar, but different approach by utilizing your normal distance prescription lens on the outside with a flexible lens built into the frame which contains a clear liquid that is easily adjusted via the slider on the nose piece mimicking how a normal eye changes lens shape and ultimately clarity. One advantage of this lens system is that it can correct for a high level of astigmatism. It is rumored these start at $700, and do not appear targeted at helping those outside that price range.
You can watch the father of adjustable eyeglasses, Joshua Silver, discuss them at this TED talk: