I See

While these aren’t going to work to replace my tri-focals, three pairs of them would.

These are water filled lenses that individuals can adjust to their own needs, then freeze the correction.

Silver has devised a pair of glasses which rely on the principle that the fatter a lens the more powerful it becomes. Inside the device’s tough plastic lenses are two clear circular sacs filled with fluid, each of which is connected to a small syringe attached to either arm of the spectacles.

The wearer adjusts a dial on the syringe to add or reduce amount of fluid in the membrane, thus changing the power of the lens. When the wearer is happy with the strength of each lens the membrane is sealed by twisting a small screw, and the syringes removed. The principle is so simple, the team has discovered, that with very little guidance people are perfectly capable of creating glasses to their own prescription.

— The Guardian

While there are definitely vision correction issues that aren’t solved by this (like astigmatism), in places like sub-Saharan Africa, the ratio of opticians to general population is approximately one to a million.  This would change the quality of life of millions of people.

link at Core77   Pointed to by Rebecca Watson Tweet.

4 thoughts on “I See

  1. This is great — I really hope this takes off. I’ve often thought about how long I’d last if I didn’t have access to an optometrist.

    And as someone who’s currently up to four pairs of glasses the idea of being able to casually adjust the prescription is quite alluring.

    I wonder if they could get it so a general prescription could be established using the syringes and then add a reservoir with a lever/slider/dial that could be used to fine-tune the lenses for distance vs. reading, etc.

  2. Hmm. Cool.

    But unless I am mistaken, they wouldn’t work for nearsighted people. Only farsighted people. Because the lenses would have to be convex. So, no joy for people like me, who are horrendously nearsighted.

    Nevertheless, these could end up benefiting lots of people.

  3. Josh Silver’s website
    http://www.physics.ox.ac.uk/ebit/joshsilver1.asp

    links to his company website
    http://www.adaptive-eyecare.com/technology.htm

    which says
    “The power range of our lenses is +6 to -6 Dioptres”

    So it looks like they can correct moderate near or farsightedness (but not, as Steve says, astigmatism).

    Based on Silver’s paper from 2003
    Ophthalmic and Physiological Optics 24:234-241, they get negative dioptres when there is less than V_0 = 2cc of liquid in the chambers, so I think that they are getting concavity by sucking the membranes in as liquid is drawn out of the chamber. Based on this paper, at least, they are using a liquid with a high refractive index (1.579) rather than water.

    Cool stuff =)

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