Actually, he's exactly right. Eyeglasses look right (aesthetically)
when the pupil is somewhere in the vicinity of the center of the lens.
And, for the thinnest and most consistent edge thickness with a minus
prescription, you want a smaller lens with the PD centered in the
lens, and a shape approaching round.
You're also right, though. The PD can be placed anywhere you want. I
have even had big aviator sunglasses. The optical center was nearer
the bridge than the hinge, and they worked just fine.
Nothing wrong with being analytical.
-- Chuck Knight
On Thu, Jun 4, 2009 at 4:41 AM, clarity <[email protected]> wrote:
>
> The PD is the pupil distance.
> Your PD is 63.5 total
> A lens is a circle with a centre that gets cut into the shape of a
> frame.
> When the person who is making your glasses "marks up" the lenses to be
> cut into the frame she marks the optical centre of the lens, tells the
> cutting machine the dimensions of the frame and the lens is cut.The
> optical centre of the lens is automaticly centered at the point of
> your PD. if the Optimum vision is not achieved through where YOUR
> PUPIL sits behind the lens then it has not been cut properly.
> I think you are trying to learn too much about your glasses and you
> are over analysing, and you have ended up missing the point entirely
> by attempting understand all this by yourself with no qualified
> optician to help you reach these strange conclusions!! .You dont need
> to try and find a frame that has the centre near the centre of your
> pupil!! The lenses are centred.Why do you think they even take a PD?
> - to put the optical centre right on it!!
>
>
> On Jun 4, 11:24 am, Paul <[email protected]> wrote:
>> I forgot to mention one thing about getting well-centered lenses. It
>> finally sunk in from your note (after only half reading another post a
>> long time ago) that the way to do it is to get bridge width plus lens
>> width (really half of one lens width plus half of the other lens
>> width) to be close to your PD.
>
> >
>
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