near and far PD and spl
Jennah
look! I am planning on ordering a pair of sunglasses from Zenni (seem
to like the frames best there, so I'm willing to give it a try) to try
things out. I have worn the same prescription since 11th grade (I am
now 24) and contacts just don't work for me. Here's what I'm trying to
figure out...
1. On my prescription from the doc, under the Left CYL, it says (what
looks like) "spL". I am thinking this means 'spectacle' and that value
should be zero. My right eye is the bad one, and iirc, I don't really
need anything in the left eye really, and the -.50 value for Left SPH
just gives me 20-15 vision with my glasses on. Am I right??
2. I got my PD measured today at Wal-Mart (where I used to go for
cheap glasses - but their lenses are so expensive!). This is what the
girl wrote: FAR PD R 28.5 L 28.5; NEAR PD 57.0.....So is my PD
57? I use my glasses to see far away, if that makes any difference...
I'm going to start out with the basic mid-index and nothing special.
But I'm excited that I may be able to get a pair of cheaper
photochromatic lenses (I hate carrying both sunglasses and regular for
outside events) and just be able to have fun glasses in general.
Hopefully my prescrip continues to stay the same - otherwise I'll have
to research these places for re-lensing like 10 pairs of glasses!
powrwrap
> 1. On my prescription from the doc, under the Left CYL, it says (what
> looks like) "spL". I am thinking this means 'spectacle' and that value
> should be zero. My right eye is the bad one, and iirc, I don't really
> need anything in the left eye really, and the -.50 value for Left SPH
> just gives me 20-15 vision with my glasses on. Am I right??
I had the same indication for cylinder as you--spL, but mine looked
like sph. In any event, it means zero, or no adjustment.
> 2. I got my PD measured today at Wal-Mart (where I used to go for
> cheap glasses - but their lenses are so expensive!). This is what thegirl wrote: FAR PD R 28.5 L 28.5; NEAR PD 57.0.....So is my PD
>
> 57? I use my glasses to see far away, if that makes any difference...
Yep, your PD is 57.0.
Jennah Watters
has one blank for PD (as far as I've seen) - so should '57' go there?
I really don't want to have to get measured again, but do you think
the measurements are questionable because the values are the same?
On 9/24/07, Doug Herr <do...@wombatz.com> wrote:
> On Sat, 22 Sep 2007, Jennah wrote:
>
> > 2. I got my PD measured today at Wal-Mart (where I used to go for
> > cheap glasses - but their lenses are so expensive!). This is what the
> > girl wrote: FAR PD R 28.5 L 28.5; NEAR PD 57.0.....So is my PD
> > 57? I use my glasses to see far away, if that makes any difference...
>
>
> Note that you were not given both the far and near PD.
>
> As you focus on something closer in, your pupils come closer
> together. So, near PD is lower then far PD.
>
>
> --
> Doug Herr
> do...@wombatz.com
>
--
K. Jennah Watters
Jennah Watters
my right eye is -2.5 and -.5 (i don't have the techincal breakdown in
front of me). I do have a smallish face (have a slightly hard time
finding sunglasses that don't look gigantor on me, for ex.), so the 57
could make sense.
I tried measuring myself with the method Ira suggested, but I had a
hard time bc I have dark brown eyes. It's near impossible to see where
the pupil starts exactly.
I suppose the little machine thing should be right - so I think I'm
gonna just go with 57...??
Thanks for all the help btw.
On 9/24/07, Doug Herr <do...@wombatz.com> wrote:
> On Mon, 24 Sep 2007, Jennah Watters wrote:
>
> > So they should not both add up to 57, theoretically? Weird. Zenni only
> > has one blank for PD (as far as I've seen) - so should '57' go there?
> >
> > I really don't want to have to get measured again, but do you think
> > the measurements are questionable because the values are the same?
>
> The PD is *much* more important if you have a very strong
> prescription.
>
> For mine, it does not make much difference. I am:
>
> -0.50 -0.25 165 +0.75 OD
> plano -0.75 040 +0.75 OS
>
> Best we can figure, I am PD 64 for far and 62 for near.
>
> Mine is much closer to the norm, with 65 (if I remember right)
> being a common default if you don't supply a PD.
>
> A single vision pair can only use one PD value. That would be
> the point where the optical center of each lens would go. A
> bifocal pair could use the two different PD values, or just take
> the distance value and subtract 2 or 3mm to do the lower part of
> the glasses.
>
> If you have a digital camera you can get a measurement yourself:
>
> 1. Place camera 1 or 2 meters away and set the auto timer.
>
> 2. First shot you focus your eyes on something in the distance,
> looking just past the camera.
>
> 3. Second shot you focus on something close, at about reading
> distance.
>
> For both shots you hold a ruler in front of your face, but close,
> touching your face, either just above or below your eyes. You
> zoom in to the pictures and use the ruler image compared to the
> distance between pupil centers to get your PD values.
>
> Clear as mud?
powrwrap
> So they should not both add up to 57, theoretically? Weird. Zenni only
> has one blank for PD (as far as I've seen) - so should '57' go there?
>
> I really don't want to have to get measured again, but do you think
> the measurements are questionable because the values are the same?
No, your opthamologist measured your PD from the center of the bridge
of your nose to the center of the right pupil and the center of the
bridge of the nose to the center of the left pupil. Congratulations,
you have a symetrical face. :-)
Your PD is 57 mm (28.5 mm + 28.5 mm) and that is what you should enter
in the form for Zenni Optical.
Jennah
Alrighty then, here goes. I'll report back on how Zenni works out. I
would go with one of the others, but there are tons of frames at Zenni
that I really like, and I haven't found much at the others.
I am still going with the assumption that the 'spL' value should be
entered as a '0'.
Thanks to both of you for your help!!