Are my polarized prescription sunglasses defective?
gendem
I recently took the plunge and got a pair of prescription sunglasses
with polarized lenses. When I got the glasses they appeared fine in
the store, but once out in the sunlight, and in situations where light
was being polarized, I immediately saw distortions in the lens.
These distortions appear as what looks like irregular nonsymmetrical
discolourations in the lens...very similar in appearance to what
engine oil looks like in a puddle, sort of muted rainbow effect. This
occurs mostly along the edges and since it's non-symmetrical leads to
a lot of "shimmering" in items reflecting light. In addition, it
appears as if the polarizaion coating is inconsistantly applied, since
looking at the sky makes it appear blotchy.
When I took them back, the person I spoke with informed me that this
is a consequence of 1. the curvature of the lens (the sunglasses are
RayBans that curve a bit around the eye) 2. the "index" of the lens
and 3. the fact that they are polarized.
I don't really buy this, I've seen many polarized sunglasses that do
not display this distortion. I know what to expect from a polarized
lens since I use them all the time with my camera.
What is going on here? Am I stuck with these lenses? I paid nearly
300 for them and I'm feeling pretty ripped off. What kind of
intelligent statements/questions do I need to put to the optometrist?
Thanks a lot in advance!
Mark A
news:abagdvsdmdjjef064...@4ax.com...
Seems to me that the real question is not what causes the problem, but
whether they offer a money back guarantee on what they sell. Some products
are guaranteed by the lens manufacturer or the lab (with a time limit). It
might be a good idea to get someone else to call your optical shop and
inquire about money-back guarantees (without specific reference to your
situation).
A lot of people don't like many of the products at LensCrafters (including
me), but they do have a 30-day money back guarantee (for any reason).
Roland J. Izaac
example 90 degrees apart, you will get reflected light from horizontal
surface eliminated through one lens while not on the other, Light reflected
of vertical surfaces would be eliminated by the other lens. therefore you
will have a strange sensation as one eye will see only reflected light off
horizontal surfaces while the other eye will see only light reflected by
vertical surface.
--
Roland J. Izaac
Mark A <m...@switchboard.net> wrote in message
news:M%WBa.949$lY5.1...@news.uswest.net...
gendem
will attempt to take pictures to show what I mean, if I ever get a
sunny day again.
As for the guarantee, I'm having a difficult time even convincing them
there is a problem at all (it's no lenscrafters though)
Thanks for the help.
Dan Abel
<gen...@yahoo.com> wrote:
> When I took them back, the person I spoke with informed me that this
> is a consequence of 1. the curvature of the lens (the sunglasses are
> RayBans that curve a bit around the eye) 2. the "index" of the lens
> and 3. the fact that they are polarized.
>
> I don't really buy this, I've seen many polarized sunglasses that do
> not display this distortion. I know what to expect from a polarized
> lens since I use them all the time with my camera.
I don't think I'm going to be of much help here, but I'll throw in my two
cents. Despite what Otis claims, the human eye is different in many ways
from a camera. A camera only takes pictures straight ahead. The eye can
move around, and so the lens must do its job through many focal planes.
I'm sure the wrap makes the glasses look better, and helps protect the eye
from sunlight, but it makes it nearly impossible to design a lens without
distortion. Although $300 seems like a lot of money for glasses, I'm sure
you spend lots of money on camera lenses that only have to work straight
ahead. Also, the high index (if that's what you have) causes additional
distortion. Camera lens are generally very high quality, but nobody would
be willing to carry around that kind of weight on their head to eliminate
distortion. Camera lenses use multiple elements to eliminate distortion,
but since eyeglass lenses need to be ground to order, that option isn't
feasible.
--
Dan Abel
Sonoma State University
AIS
da...@sonic.net
Mark A
> Good point. I'm not sure the lenses are that far apart, however. I
> will attempt to take pictures to show what I mean, if I ever get a
> sunny day again.
>
> As for the guarantee, I'm having a difficult time even convincing them
> there is a problem at all (it's no lenscrafters though)
>
> Thanks for the help.
>
guarantee. They may have one (with a time limit), but won' t admit it to
you.
Mike Tyner
and sometimes the stress of forcing them into the frame, creates scalloped areas
around the edges where the polarization effect drops off or gets distorted.
The best way to check polarized glasses is put on some OTHER polarized lenses
(like Foster Grants) and look at your lenses as you rotate them through 360
degrees. Stress defects jump out at you.
-MT
"gendem" <gen...@yahoo.com> wrote in message
news:abagdvsdmdjjef064...@4ax.com...
Rishigg
> from a camera. A camera only takes pictures straight ahead. The eye can
> move around, and so the lens must do its job through many focal planes.
The camera is different for two reasons:
1) it has not a mind that treats the signal
2) it has not a visual field to bebuilt in the mind by means of the isgnal.
Roland J. Izaac
both lenses is to hold the pair of spectacles to a LCD screen. viewing the
screen through the lenses, rotate the lenses. as you rotate the lens the
image on the screen will black out at some angle. If both lenses black out
at the same angle, both lenses have the same polorization angle. on my LCD
screen the angle is correct when the frame is horizontal. Another test is to
look for a reflection on a horizontal surface, rotate the lens around, the
reflection should come and go ass you rotate them. If this does not happen,
change your angle of view till it does. If the frame is horizontal when the
reflection is reduced or eliminated the angle is correct. else it is not. I
once purposly made up a pair of polorized lenses with one angled horizontaly
the other angled vertically. I walked through a shopping centre with glasses
windows on the right and left of me. reflection off the glasses pannel were
eliminated from my right eye, but not from my left. It felt like the
reflections were jumping at me in a sort of #D effect. It felt really weird.
--
Roland J. Izaac
gendem <gen...@yahoo.com> wrote in message
news:uodhdvsj60qgbm55n...@4ax.com...
Specs31
>occurs mostly along the edges and since it's non-symmetrical leads to
>a lot of "shimmering" in items reflecting light.
You first need to mayb have an understanding of what you have and than the
other might make a little more sense :-) .. a polarized lens is actually
"de-polarizing" polarized light, the polarized film is either applied to the
top surface (very OLD way of doing it) on sandwiched between a wafer and the
rest of the lens (also called injected, casted andnow laminated which really
was the phrase for the original crappy kind) .. this sheet is made mostly of
iodine and alcohol and what it does is blocks light (glare) other than at a
degree angle (the formula is called brewsters law) .. now this lens can be a
pain in the rump if it is not done properly, which in this case it was NOT done
so, those distortions in the polarized field are due to stress on the polarized
sheet, it is very simple to check if the lens were taken out of the frame and
they let them set for a few minutes I'll bet you a ton of money that that
distortion "magically" goes away :-)
> 1. the curvature of the lens (the sunglasses are
>RayBans that curve a bit around the eye)
WRONG, that "curve" will disort "images" and acuity if it is to far off of the
best curve for your correction but it will NOT have any bearing on the
polarized sheet and it being distorted.
> 2. the "index" of the lens
>and
WRONG again, the index of refraction of the material will have ZERO bearing
on the way the sheet is seen
> 3. the fact that they are polarized.
>
WRONG, I would run from these guys, they have no clue about optics and do not
understand anything about polirization
degree off as someone else stated, this would not be the same effect, what you
would have if the sheets were
The lens base curve (amount of curve to the lens front) and the base curve
of the frame are NOT the same and someone "forced" it into a frame, also it
probably is not fit correctly which adds to the stress disortion in the sheet
(which is what you are seeing)
degree's off is one lens would be de-polarizing and the other would be doing
noting, you would see a lot of glare on one side as you looked through and none
on the other...
What Mike was talking about is "cross polarizing" where you take another
polarized lens and hold it face to face with your frame and as you rotate them
in opposite directions and look at a light source the lens appear to turn
"black" the darker the "blackness" the better the quality of polarized lens :-)
.. both lens should turn black (left and right) at the same position as you
rotated them, this will tell you if one polarized sheet is off axis or not.
You my friend got shoddy craftsmenship, nothing more nothing less.. I own
a wholesale optical lab and here in FL. I probably do more than my fair share
of polarized lens..hmm, in poly, high index and glass materials.. including a
TON of wrap frames...
Jeff