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Thread: Smoke and mirrors: Rx lens technology circa year 2020 ..?

  1. #1
    Master OptiBoarder rinselberg's Avatar
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    Smoke and mirrors: Rx lens technology circa year 2020 ..?

    Eyes like a hawk

    New Scientist: 25 November 2000
    Eugenie Samuel; Magazine issue 2266


    One day your optician could give you superhuman eyesight.


    THINK you've got perfect vision? Think again. Pablo Artal reckons he can double the sharpness of anybody's vision, no matter how good it is to start with. He revealed his "smart spectacles" technology at a conference on adaptive optics in Murcia, Spain, last week.

    Few people would choose to wear Artal's prototype, as the computer hardware it relies on takes up a full square meter of desk space. "But the key optical component is very small and cheap," says Artal, a researcher in the optics laboratory at the University of Murcia.





    Schematic of "smart spectacles" lens technology: All they have to do is make it small enough and light enough to wear as a spectacles frame ...


    Conventional spectacles correct for poor focusing and astigmatism in the eye's lens. But almost everyone has subtle additional faults which vary as their pupils dilate and their eyes focus. To try and correct for these problems, Artal and his colleagues turned to the techniques of adaptive optics, which are more commonly used in telescopes and spy satellites.


    There are three discernible uses for adaptive optics: One is to increase the resolution of ophthalmoscopes, in order to see more detail of the retina; the second is the possibility to improve vision--and finally the ability to perform new experiments in vision research with purposely manipulated (but not corrected) optical aberrations.
    Pablo Artal, 2005. Source: http://www.harnessinglight.org/artal.htm


    In adaptive optics, light from a star (typically) is bounced off a mirror which changes shape to compensate for the distortions introduced by fluctuations in the atmosphere. It is these fluctuations in the density of the atmosphere that make stars twinkle. Artal's spectacles do the same thing for transient imperfections in the eye, correcting for them 25 times every second. "Everything sharpens up as you switch on," he says.

    In his prototype spectacles, a low-intensity infrared laser beam bounces off the back of the retina and into a sensor via a deformable mirrored membrane. The membrane's shape is controlled by an electric field created by a microchip underneath it.

    A computer works out how much the infrared beam has been distorted by the eye's lens and tells the mirror chip to deform the mirror in real time (see Diagram). Because light reaches the user's eyes via the deformable mirror, the computer can ensure that the user sees a perfect image.

    The mirror's shape is updated 25 times per second--about 5 times faster than aberrations vary in the eye, so the wearer is unaware of the moving mirror.

    Artal says that someone wearing the new specs can see small objects at a range of 12 meters that someone with 20/20 vision cannot see, even from as close as only 6 meters. But Fred Fitzke, an ophthalmologist at University College London, is more cautious: "At the moment, we don't know what other limits there are to vision--like the structure of photoreceptors in the eye, or whether the brain can even use the extra information. But I look forward to finding out with this kind of device."

    As well as having possible military applications, the super specs can be used in reverse to take real-time precision images of the retina. "You can use it to take microscopic images of individual cells and diagnose eye diseases very early," says Austin Roorda of the University of Houston.


    For more:

    Optics Express (2006): Adaptive optics with a magnetic deformable mirror: applications in the human eye

    Journal of Vision (2004): Neural compensation for the eye’s optical aberrations
    Last edited by rinselberg; 01-02-2007 at 05:19 AM.

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    ATO Member HarryChiling's Avatar
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    no longer playing in this sand box
    Last edited by HarryChiling; 02-21-2007 at 04:52 AM.
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    My Bad....

    I saw the title and didn't finish reading it.

    "Smoke and mirrors: Rx lens.....


    Here I thought it was another rant about bogus lens marketing, and all the BS that goes along with it.

    oops..silly me!;)

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    Quote Originally Posted by HarryChiling View Post


    Probably not, the other O's will just try to find a way of saying it is somehow an integral part of their profession and that opticians should not be abe to provide it. ;)
    What an idea.

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    I think there was another thread on the board related to this. It was research that showed that the difference between people that had 20/20 vision and those that had 20/15 vision was in the visual processing, not in the optics of their eyes; if I am remembering correctly.
    So if the corrective processing of the image is done BEFORE it enters the eye, it should be able to help some people (20/20 and worse) but not others (20/15)

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    well yes a great deal of imperfections are compensated due to mental focus, saccadic movements, etc.

    but there are still going to be residual issues which I guess the adaptive optics might resolve.

    Just as some people adjust more readily to particular lens materials and designs, of course there will be variance in improvement with adaptive technologies.

    My question is whether more loss of acuity, in real-world applications, comes from external factors....like foreign particles and moisture on lens surface. Current technologies such as scopes are obviously operating under controlled conditions.

    It seems that smudged lenses would fall under the category of "fluctuations in the atmosphere"...well....at least the external surface of the lens. Again, in a scope, the internal surface of the lens is shielded, in eyeglasses, it is not.

    It appears that this process is working in reverse of the scopes. The scope is analysing only external variations in optics (since the internal environment can be well controlled). This new device is analysing changes internal to the lens surface. It is unclear whether this process can or should work in both directions, simultaneously? I would think not. The scope is examining the appearance of the star; this new device examines the appearance of the retina.

    Fascinating post.

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    Quote Originally Posted by HarryChiling View Post
    I have always wondered how much more improvement can you make when the fovea is where the sharpest vision is and it's area is so small. Would these lenses be more beneficial at night as compared to the day, since the rods take over for vision and are more widely spread out than the cones? Very interesting stuff.
    It is generally thought that in the absence of any aberration, the density of cones at the fovea would allow for about 20/7.5 vision. However, most of us are far from that perfect and it maybe the case that the visual cortex is not capable of developing that level of acuity.

    A vision correction system such as this would provide more improvemnt during low light conditions b/c of the additional abberations that are induced during pupil dilation, more of the cornea's (and the lens I suppose) surface becomes involved in the formation of the retinal image. The marketing material from izon/ophthalonix makes a big deal of this, specifically for night time driving.

    The night time improvement would not be due to the contribution from rods b/c the rods do not provide a very fine level of visual acuity, due to their density distribution and absence at the fovea.

    What I doubt though, is that a continously adapting spectacle would provide much more benefit in the everyday application than somthing like the izon lenses (though I know the jury here still seems to be out on that issue). Would be a very useful vision research tool though!

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