> In article
> <0cc0187e-5306-418d-b77b-233a737ea...[at]s19g2000vbp.googlegroups.com> ,
> *AndyHancock <AndyMHanc...[at]gmail.com> wrote:
> > On Mar 31, 10:57 am, "Mike Tyner" <mty...[at]mindspring.com> wrote:
> > > "AndyHancock" <AndyMHanc...[at]gmail.com> wrote> > What I am saying is that human recall of imagery is poor for
> > comparative purposes. *The blurriness itself is a major pain. *In many
> > domains, even optics, quickly modulating an input variable (the lenses
> > in this case) to see its effects on an output variable (the blurriness
> > in this case) is often used in lab experiments to make the differences
> > noticable in spite of human shortcomings. *It does not imply that the
> > difference is negligible.
> > > Why bother?
> > To solve the blurriness when gazing off-axis.
> Wouldn't it just be simpler to not allow things to be off axis?
> :-)
> Seriously, you may wish to try contacts. *As they move with the eye,
> they are never off axis. *They will also eliminate the minification you
> get with eyeglass correction using glasses, which is significant at your
> correction.

> On Wed, 1 Apr 2009 02:31:23 -0700 (PDT), AndyHancock <AndyMHanc...[at]gmail.com> wrote:
> > On Mar 30, 4:48*pm, Robert Martellaro <rob...[at]nospam.com> wrote:
> > > On Sun, 29 Mar 2009 09:03:52 -0700 (PDT), AndyHancock <AndyMHanc...[at]gmail.com> > > wrote:
> > > > I owned glasses for about *10-15 years before replacing them. *They
> > > > were aspheric lenses from a reputable glasses shop, and image was
> > > > blurry when I gaze about 30-40 degrees away from centre i.e. my
> > > > eyeball is rotated so that pupil is staring through a point on outer
> > > > side (left/right) of the lens. *High index plastic with AR and scratch
> > > > resistant coatings. *I am not concerned about bending of straight
> > > > lines, or prism effect where edges seem to bleed different colors.
> > > > The simple blurriness was the main thing I was trying to solve. *
> > > Transverse chromatic aberration can cause off-axis blur, so I wouldn'trule out
> > > that prism effect as the cause of your problem.
> > Would there not be telltale signs of color separation?
> I don't see the color fringing, just the blur. It might depend on the
> individual, and on the level of contrast- color fringing might be more
> noticeable in high contrast conditions like black print on white paper under
> strong lighting.

> > > Asphericity allows the use of flatter base curves (flatter curves reduce
> > > magnification, minification, weight, and look better cosmetically, especially
> > > with higher plus powers) without increasing oblique astigmatism and power error.
> > > Except for plus powers over about eight diopters, the off-axis performance of
> > > spherical and aspherical lenses will be the same, assuming the use of best form
> > > base curves. *
> > > Post your Rx and lens specifics like material and index of refraction and I'll
> > > try to pinpoint the reason for the blurring.
> > Paperwork seems to have gone missing...I shall try to get another copy
> > from the optician. *They are for short-sightedness, I believe 4.5-5.5
> > diopts depending on the eye. *High-index plastic, I think, though this
> > is probably important enough to need being sure about. *As well as the
> > brand name and make. *I shall try to get those details, though the
> > shop has been closed on Saturdays for the last number of weeks despite
> > the schedule stating they are open. *I don't suppose the vague details
> > above are enough bases for reasoned speculation?
> The more information the better. Five diopters is certainly strong enoughto
> make the off-axis blur noticeable for some individuals, if you're using ahigh
> dispersion lens material; i.e. Polycarbonate, 1.67, and 1.74. Off-axis
> performance can also be compromised by using the incorrect base curves, and will
> be more pronounced by improper lens positioning.

> It should be noted that the on-axis vision (straight ahead gaze) can alsosuffer
> if lens positioning and tilt are incorrect. *In other words, your vision could
> be blurry with your new glasses even if the lens powers are exactly as
> prescribed by the doctor!

> Hope this helps, *
> Robert Martellaro
> ~~~~~~~~~~~~~~~~~~
> Optician/Owner
> Roberts Optical
> Wauwatosa Wi.
> ~~~~~~~~~~~~~~~~~~
> "Science is a way of trying not to fool yourself."
> - Richard Feynman

> On Mar 30, 4:48*pm, Robert Martellaro <rob...[at]nospam.com> wrote:
> > On Sun, 29 Mar 2009 09:03:52 -0700 (PDT), AndyHancock <AndyMHanc...[at]gmail.com> > wrote:
> > > > I owned glasses for about *10-15 years before replacing them. *They
> > > were aspheric lenses from a reputable glasses shop, and image was
> > > blurry when I gaze about 30-40 degrees away from centre i.e. my
> > > eyeball is rotated so that pupil is staring through a point on outer
> > > side (left/right) of the lens. *High index plastic with AR and scratch
> > > resistant coatings. *I am not concerned about bending of straight
> > > lines, or prism effect where edges seem to bleed different colors.
> > > The simple blurriness was the main thing I was trying to solve. *
> > > Transverse chromatic aberration can cause off-axis blur, so I wouldn't rule out
> > that prism effect as the cause of your problem.
> Would there not be telltale signs of color separation?

> > Asphericity allows the use of flatter base curves (flatter curves reduce
> > magnification, minification, weight, and look better cosmetically, especially
> > with higher plus powers) without increasing oblique astigmatism and power error.
> > Except for plus powers over about eight diopters, the off-axis performance of
> > spherical and aspherical lenses will be the same, assuming the use of best form
> > base curves. *

> > Post your Rx and lens specifics like material and index of refraction and I'll
> > try to pinpoint the reason for the blurring.
> Paperwork seems to have gone missing...I shall try to get another copy
> from the optician. They are for short-sightedness, I believe 4.5-5.5
> diopts depending on the eye. High-index plastic, I think, though this
> is probably important enough to need being sure about. As well as the
> brand name and make. I shall try to get those details, though the
> shop has been closed on Saturdays for the last number of weeks despite
> the schedule stating they are open. I don't suppose the vague details
> above are enough bases for reasoned speculation?

> On Mar 31, 10:57 am, "Mike Tyner" <mty...[at]mindspring.com> wrote:
> > "AndyHancock" <AndyMHanc...[at]gmail.com> wrote
> What I am saying is that human recall of imagery is poor for
> comparative purposes. The blurriness itself is a major pain. In many
> domains, even optics, quickly modulating an input variable (the lenses
> in this case) to see its effects on an output variable (the blurriness
> in this case) is often used in lab experiments to make the differences
> noticable in spite of human shortcomings. It does not imply that the
> difference is negligible.
> > Why bother?
> To solve the blurriness when gazing off-axis.

> cheaper. I'm assuming that using 2 frames that are identical may be
> more reliable (though I don't know for sure).

> On Sun, 29 Mar 2009 09:03:52 -0700 (PDT), AndyHancock <AndyMHanc...[at]gmail..com> wrote:
> > I owned glasses for about *10-15 years before replacing them. *They
> > were aspheric lenses from a reputable glasses shop, and image was
> > blurry when I gaze about 30-40 degrees away from centre i.e. my
> > eyeball is rotated so that pupil is staring through a point on outer
> > side (left/right) of the lens. *High index plastic with AR and scratch
> > resistant coatings. *I am not concerned about bending of straight
> > lines, or prism effect where edges seem to bleed different colors.
> > The simple blurriness was the main thing I was trying to solve. *
> Transverse chromatic aberration can cause off-axis blur, so I wouldn't rule out
> that prism effect as the cause of your problem.

> > After
> > many adjustments (about 1.5-2 hours each, including travel), I simply
> > went back to my old, old glasses. *I did the reading about the
> > different aberrations, the various fitting
> > Now , more than half a decade later, I tried again with another
> > reputable glasses shop. *Same problem, despite follow-up checks on
> > adjustment. *Rather than bothering the people (and myself) with
> > repeatedly with futile adjustments, I decided to buy a second pair of
> > glasses, everything the same except with spherical lenses.
> > Unfortunately, the frame was no longer available (this is about a
> > month after receiving my first new glasses). *So I can't do an
> > experiment where all factors (including the frame and the glass shop)
> > are the same except whether the lens is spherical or aspherical.
> > Rather than compromise the experiment, I decided to read up (again).
> > According tohttp://en.wikipedia.org/wiki/Aspheric_lens, aspherics
> > improve cosmetics, but not vision.
> > In contrast,http://www.allaboutvision.com/lenses...ric-lenses.htm
> > says that aspherics reduce distortion when gazing off-centre, though
> > it doesn't say whether they are referring to blurriness (see section
> > "Superior Optics of Aspheric Lenses" -- the reference to clear imaging
> > seems to refer to blurriness, or lack thereof). *This is the *only*
> > site I've found that indicates an improvement in vision. *All other
> > explanation of asphericity shows columnated light approaching a lens
> > along its longitudinal axis, and showing a single point focal point
> > instead of the smeared focal point of spherical lenses.
> > I have two questions in the following paragraphs that I'm hoping the
> > experts here could respond to.
> > I asked at another optical outlet about aspherics...whether it is
> > meant to optimize parts of an image that is well off-centre when the
> > user is gazing out the optical centre, or whether it optimizes the
> > central part of the image when a user's eyeball is rotate away from
> > the optical centre. *Apparently the latter, and the above site on
> > "Superior Optics of Aspheric Lenses" corroborates. *Is this true?
> Asphericity allows the use of flatter base curves (flatter curves reduce
> magnification, minification, weight, and look better cosmetically, especially
> with higher plus powers) without increasing oblique astigmatism and powererror.
> Except for plus powers over about eight diopters, the off-axis performance of
> spherical and aspherical lenses will be the same, assuming the use of best form
> base curves. *
> > Since I can no longer obtain the frames that I have (verified by
> > contacting suppliers through-out North America), and I'm not a web-
> > buyer, would there be any merit to any experiment where the frames for
> > the aspherics differ from my current frames for the aspherics?
> > Thank you.
> Post your Rx and lens specifics like material and index of refraction andI'll
> try to pinpoint the reason for the blurring.

> In article
> <acb831b3-8e3b-402a-afa8-554a67106...[at]l13g2000vba.googlegroups.com> ,
> *AndyHancock <AndyMHanc...[at]gmail.com> wrote:
> > I'm not completely unfamiliar with the world of optics (in dielectric
> > waveguides rather than geometric optics) and of optimization, so I get
> > the gist of your description. *It would still be nice to know whether
> > not maintaining the same frames would mess up the comparison between
> > aspheric and spheric.
> > On a separate vein, I noted some experts vigorously defend the merit
> > of aspherics, attributing the problems to fitting and dispensing. *For
> > me, it does not matter what the source of difficulties are. *If the
> > state of practice for dispensing and fitting is not mature enough to
> > be uniform and reliable for aspherics, that has the same effect as
> > unreliable aspheric technology in the design/manufacturing realm --
> > maybe even worse, since it costs much time and good will in repeated
> > attempts at refitting, and maybe even redispensing.
> I think that the frame discussion is a red herring. Seldom will you use
> the lenses near the edge. The figure of merit for optimization should
> not weigh performance looking through the lens near the periphery very
> heavily.

> The fitting of the lens into a frame will be the least of your
> problems. The opticians should have templates for edging the lenses to
> fit almost any frame. The should even be able to make a template from
> frames in hand.

> One of the tradeoffs to be used in the optimization should be the
> effects of centering error on performance.

> You should realize that various practitioners have their own biases.
> They may not even know them. While there are some out and out charlatans
> out there, you should worry at least as much about true believers.
> Remember that surgeons will lean toward cutting while pharmacologists
> would prefer all manner of drugs. Each could honestly think that their
> approach is best for the patient.
> In short, I think you have unrealistic expectation for the benefit to be
> gained by using aspheric lenses. I cannot imagine that you will not be
> disappointed.

> I am not a health professional. What little experience I have with
> aspheric design leaves me highly skeptical. What I believe, without
> proof, is that a small pupil size in bright light enables people to
> tolerate aspherics much better than the would in dim light. Moreover,
> the lens can be designed for best performance on-axis. There is where
> the benefit lies.

> "AndyHancock" <AndyMHanc...[at]gmail.com> wrote> > I would like to avoid the variation that comes from putting lenses
> > into the frame before each trial.
> So your blur problem only occurs when you first put on the glasses?
> > But more importantly, I want to be able to instantly switch, as often
> > as necessary, so that I can clearly notice the difference.
> Yes, that would be ideal but you said that wasn't possible.
> What I'm suggesting is possible, as well as the cheapest possible way to
> perform your test.

> > Otherwise, I would not have confidence in the comparison.
> Then you're telling us the difference is so small you couldn't be sure it
> actually exists.

> Why bother?

> -MT

> I would like to avoid the variation that comes from putting lenses
> into the frame before each trial.

> But more importantly, I want to be able to instantly switch, as often
> as necessary, so that I can clearly notice the difference.

> Otherwise, I would not have confidence in the comparison.

> I owned glasses for about 10-15 years before replacing them. They
> were aspheric lenses from a reputable glasses shop, and image was
> blurry when I gaze about 30-40 degrees away from centre i.e. my
> eyeball is rotated so that pupil is staring through a point on outer
> side (left/right) of the lens. High index plastic with AR and scratch
> resistant coatings. I am not concerned about bending of straight
> lines, or prism effect where edges seem to bleed different colors.
> The simple blurriness was the main thing I was trying to solve.

> After
> many adjustments (about 1.5-2 hours each, including travel), I simply
> went back to my old, old glasses. I did the reading about the
> different aberrations, the various fitting
> Now , more than half a decade later, I tried again with another
> reputable glasses shop. Same problem, despite follow-up checks on
> adjustment. Rather than bothering the people (and myself) with
> repeatedly with futile adjustments, I decided to buy a second pair of
> glasses, everything the same except with spherical lenses.
> Unfortunately, the frame was no longer available (this is about a
> month after receiving my first new glasses). So I can't do an
> experiment where all factors (including the frame and the glass shop)
> are the same except whether the lens is spherical or aspherical.
> Rather than compromise the experiment, I decided to read up (again).
> According to http://en.wikipedia.org/wiki/Aspheric_lens, aspherics
> improve cosmetics, but not vision.
> In contrast, http://www.allaboutvision.com/lenses...ric-lenses.htm
> says that aspherics reduce distortion when gazing off-centre, though
> it doesn't say whether they are referring to blurriness (see section
> "Superior Optics of Aspheric Lenses" -- the reference to clear imaging
> seems to refer to blurriness, or lack thereof). This is the *only*
> site I've found that indicates an improvement in vision. All other
> explanation of asphericity shows columnated light approaching a lens
> along its longitudinal axis, and showing a single point focal point
> instead of the smeared focal point of spherical lenses.
> I have two questions in the following paragraphs that I'm hoping the
> experts here could respond to.
> I asked at another optical outlet about aspherics...whether it is
> meant to optimize parts of an image that is well off-centre when the
> user is gazing out the optical centre, or whether it optimizes the
> central part of the image when a user's eyeball is rotate away from
> the optical centre. Apparently the latter, and the above site on
> "Superior Optics of Aspheric Lenses" corroborates. Is this true?

> Since I can no longer obtain the frames that I have (verified by
> contacting suppliers through-out North America), and I'm not a web-
> buyer, would there be any merit to any experiment where the frames for
> the aspherics differ from my current frames for the aspherics?
> Thank you.