On Oct 31, 11:26 am, Richard J Kinch <ki...[at]truetex.com> wrote:
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Best angle has reasonable precision.
Beyond threshold "best angle " is absoluttely relative, in the brain
Like people without astigmatism but wearing progressive lenses which
(that lenses) have a lot of astigmatism
even do not see that they wear astigmatic lenses.
All depends of perception.
Also it is a thing like adaptation.
When trying lenses, after changing angle few times you will not be
sensetive enough to the angle changing.
You should start again next time.

lena102938 writes:

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Matters not whether it is regular. There will still be one best angle to
apply a cylindrical correction, even if the error being corrected is not
itself perfectly cylindrical.

Mike Tyner writes:

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I would expect that. When it comes to instrumentation (physical or
musical), there are many who will just never "get it".

In article <cZednTkhw_-vZLranZ2dnUVZ_rqlnZ2d[at]giganews.com> ,
"Mike Tyner" <mtyner[at]mindspring.com> wrote:

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But do they grind them to specs? What about premade blanks?

I've probably told this story before, but here it is again:

I went to see my OD. He said I was a ten (degrees). He ordered me a
six pack. I went in a few weeks later and he overrefracted me. Not
good. He looked in my eye, and the contact was rotated. He moved it
back. That was better. He told me to blink. It rotated right back to
where it wanted to be. He tried it once more, with the same results.
So he did a calculation and said I needed a 25, but they only come in 10
degree increments, so he tossed a coin (not literally) and said I was a
30. He ordered me another six pack, even though I still had five of the
others in the box.

On Oct 30, 10:40 pm, "Mike Tyner" <mty...[at]mindspring.com> wrote:
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But they do not understand, probably,
that after you make the even perfect prescription, then OP will make
lenses which have spec. of pressision
I do not now what is presison spec. of making lenses,
But after that OP will insert lenses into frame and I am sure, that
error in angle much more than 1 deg

And then they wear glasses which slide on nose, shift, bend and so on,
so on, so on

"Richard J Kinch" <kinch[at]truetex.com> wrote

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The greater the cylinder power, the more it matters. I always specify to the
degree, but with 050 cylinder you can repeat the test three times and get
three different answers.

I've guided many hands up to the axis wheel to let them confirm my
cross-cylinder results. Some people are wildly unreliable or inconsistent on
the crossed-cylinder tests.

-MT

On Oct 30, 9:53 pm, Richard J Kinch <ki...[at]truetex.com> wrote:
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If you have absoluttely "regular" asrigmatism, which is almost
impossible in real eyes.
Also if you astigmatizm is large it is detectable.
Astigmatism like cyl +1 or -1 and angle 1deg? Imagination.

Mike Tyner writes:

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As a final step I insist my optometrist let me fine tune the cylinder angle
by me tweaking the trial lenses in the trial frame while I look at an
astigmatism target. I can refine that within 1 degree of optimal, better
than the 5 degree increments usually specified. Unlike power, the angle
seems like something you can trust the (knowledgeable) patient to optimize.

Dear Lena,

Subject: The OD takes a refractive-STATE "snap-shot"
once every two years.

Lena> Is somebody ever was thinking that eyes constantly
moving and changing shape? (forget accommodation)

Otis> In an engineering-scientific sense? Yes, of course
they even made a motion-picture of the eye's adaptiveness.

Otis> A picture is worth 1,000 words. And animation of
the natural eye's dynamic adjustments -- is worth
10,000 words. Watch the blue tint animation of the
eye's change -- with applied minus and plus lens.


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Otis> Yes it is. The performance is EXPECTED and
confirmed. (But denyed by the powers-that-be.)

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Otis> The natural eye is a high-performance control
system -- in all respects.

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Otis> Profound -- modern technology only gets "close".


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Otis> With they are in total denial of

Otis> Watch the natural and fundamental eye
change it refractive STATE will applied plus and
minus lenses.


http://vision.berkeley.edu/wildsoet/myopiaprimer.html

Otis> How much clearer can this be???

Otis> Why the denial of these objective scientific facts
by the majority opinion ODs?


On Oct 30, 8:58 pm, lena102938 <db00q...[at]yahoo.com> wrote:
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On Oct 30, 9:12 pm, "Mike Tyner" <mty...[at]mindspring.com> wrote:
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True.