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| Liz... |
 Posted: Fri Oct 09, 2009 5:05 pm |
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I found graphs, tables, and primary literature for how much UV is
blocked by IOLs.
I hadn't looked before. I'd assumed that all current monofocal IOLs
would block virtually all UV light (<400 nanometers).
Not so.
Tecnis acrylic untinted lenses transmit quite a bit of light in the
380-400 range. (If you want the graphs, email me.)
Alcon's untinted acrylic lenses appear to do better. Their abrupt
rise in transmittence occurs in the visible range, not the UV.
However, their literature is kind of a mess, so the numbers may not be
right.
I keep reading of many brands of IOL out there besides Tecnis (AMO),
Acrysof (Alcon), and Bausch&Lomb. I wonder about them. My docs don't
mention them, except as specialty lenses (for patients with medical
issues other than just cataract).
This is discouraging.
Questions:
1) Do other brands of lens come to mind that combine the (presumed)
visual sharpness of a negative aspheric and high abbe number (etc etc)
with better UV blocking?
3) Are all those other types (eg Allergan, Chiron, IOVISION, Mentor,
Ophtec, Pharmacia, Staar, Storz) still in use? Should I look into
them?
If you have the Tecnis, you might able to see UV light.
The retina can pick it up, people without UV-blocking lenses can see
it, and I'd guess that the UV that they see is just south of 400
(probably the tail end of the sensitivity of our blue cone)... in the
same range that the Tecnis transmits.
3) So, those who have Tecnis, is any UV visible?
cheers,
Liz |
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| Liz... |
| Posted: Sun Oct 11, 2009 7:15 pm |
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CONT.
It seems that most doctors prefer to use only a small selection of
lenses, because they have to learn how to get the best results with
each kind; the fewer they use, the more reliable their results.
So I rescind my questions about those other kinds, until I find out
whether my doc even uses them.
But I sure would like to know if those of you wearing the recent
acylic Tecnis can see UV.
L.
(BTW, the suggestion by Dan, Neil, and others to make appointments
with surgeons and talk to them was a good one. This method has been
extremely productive, both in getting information and in finding a
good doc.) |
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| Neil Brooks... |
| Posted: Mon Oct 12, 2009 5:31 am |
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On Oct 11, 11:15 pm, Liz <fraternobom... at (no spam) yahoo.com> wrote:
[quote:182e051a41]CONT.
It seems that most doctors prefer to use only a small selection of
lenses, because they have to learn how to get the best results with
each kind; the fewer they use, the more reliable their results.
So I rescind my questions about those other kinds, until I find out
whether my doc even uses them.
But I sure would like to know if those of you wearing the recent
acylic Tecnis can see UV.
L.
(BTW, the suggestion by Dan, Neil, and others to make appointments
with surgeons and talk to them was a good one. This method has been
extremely productive, both in getting information and in finding a
good doc.)
[/quote:182e051a41]
Glad you're moving in the right direction, Liz -- if only on a FEW of
the many fronts.
Sounds like you're /really/ going at this the right way. Take your
time, try to put logic in front of any possible emotion, stay
methodical, get what you need (questions answered), and ... trust your
gut. |
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| Mike Tyner... |
| Posted: Mon Oct 12, 2009 8:19 am |
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Liz, "ultraviolet" means "beyond the visible spectrum" (Mirriam-Webster)
because normal human photoreceptors don't respond to those wavelengths.
When someone can "see" light from a UV source, it's either emitting non-UV
or fluorescencing into the visible range.
Many UV filters look yellow because they block some visible blue also.
-MT
"Liz" <fraternobombus at (no spam) yahoo.com> wrote in message
news:ed4f22a3-676e-4078-a2c7-6e945e1af94d at (no spam) a21g2000yqc.googlegroups.com...
[quote:cb8f84b24e]CONT.
It seems that most doctors prefer to use only a small selection of
lenses, because they have to learn how to get the best results with
each kind; the fewer they use, the more reliable their results.
So I rescind my questions about those other kinds, until I find out
whether my doc even uses them.
But I sure would like to know if those of you wearing the recent
acylic Tecnis can see UV.
L.
(BTW, the suggestion by Dan, Neil, and others to make appointments
with surgeons and talk to them was a good one. This method has been
extremely productive, both in getting information and in finding a
good doc.)
[/quote:cb8f84b24e] |
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| Liz... |
| Posted: Tue Oct 13, 2009 10:04 am |
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[quote:71be9117b5]"ultraviolet".... normal human photoreceptors don't respond to those wavelengths.
When someone can "see" light from a UV source, it's either emitting non-UV or fluorescencing into the visible range.
[/quote:71be9117b5]
No, Mike, it really is true that our retinas can detect UV. This is
in the literature; I probably can't find the source. I'm also not
sure which wavelengths of UV - I'd assume it would have to be the
longest ones, but have not checked. UV is normally blocked by the
biological lens, of course, so only those who've had the lens removed
can ever see it. And I don't think they see it all that brightly.
But it is visible.
I swear this is true, hunt around. It's been a topic of discussion
on the birdchat, scientific illustration, and some plant lists.
It's surprising, and it sure makes me curious to know what it looks
like.
cheers,
Liz |
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| Liz... |
| Posted: Tue Oct 13, 2009 6:40 pm |
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[quote:e38beb58d4]See:http://starklab.slu.edu/humanUV.htm
[/quote:e38beb58d4]
Yes! And see also this fascinating photo:
http://starklab.slu.edu/lens.JPG
It's some human lenses (not gross, are OK to look at) from people of
different ages. Look how yellow they get!
[quote:e38beb58d4]No, Mike, it really is true that our retinas can detect UV. This is
in the literature; I probably can't find the source. I'm also not
sure which wavelengths of UV -
See:http://photo.net/learn/optics/edscott/eyespect.jpg
[/quote:e38beb58d4]
I see it... thanks. I also spent part of this evening, out of
curiosity, online at the university library trying to find a decent
reference on human reception of UV. I found a few, but it sounds
uncommon.
[quote:e38beb58d4]Spectral sensitivity is bell-shaped and there are no absolutes. Likewise the
nomenclature is expected to be flexible. Choosing any arbitrary number like
400 nm means you will be "wrong" for some percentage of cases.
[/quote:e38beb58d4]
That must be it.
I suspect that the people who do see UV are looking for it, and that
this is not many people. A man formerly on the illustration list
supposedly could see the UV patterns on orchids after his cataract
operation, but he died, so we have only anecdote.
However, I still feel that an IOL should block most light below 400
nm, just for health reasons, and many don't. I guess I won't be
getting those.
cheers,
Liz
Indy |
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| Mike Tyner... |
| Posted: Tue Oct 13, 2009 8:41 pm |
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"Liz" <fraternobombus at (no spam) yahoo.com> wrote
[quote:588c1a3df5]It's surprising, and it sure makes me curious to know what it looks
like.
[/quote:588c1a3df5]
See: http://starklab.slu.edu/humanUV.htm
[quote:588c1a3df5]No, Mike, it really is true that our retinas can detect UV. This is
in the literature; I probably can't find the source. I'm also not
sure which wavelengths of UV - I'd assume it would have to be the
longest ones, but have not checked. UV is normally blocked by the
[/quote:588c1a3df5]
See: http://photo.net/learn/optics/edscott/eyespect.jpg
Spectral sensitivity is bell-shaped and there are no absolutes. Likewise the
nomenclature is expected to be flexible. Choosing any arbitrary number like
400 nm means you will be "wrong" for some percentage of cases.
-MT |
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| Liz... |
| Posted: Wed Oct 14, 2009 4:55 am |
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[quote:fb2db0b0f1]However, I still feel that an IOL should block most light below
400 nm, just for health reasons, and many don't. I guess I won't
be getting those.
In glasses, "UV coatings" aren't yellow.
[/quote:fb2db0b0f1]
OK. But... I don't understand. How does that relate to what we were
just talking about?
thanks,
Liz |
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| Mike Tyner... |
| Posted: Wed Oct 14, 2009 8:31 am |
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"Liz" <fraternobombus at (no spam) yahoo.com> wrote
[quote:7d74e1de30]However, I still feel that an IOL should block most light below
400 nm, just for health reasons, and many don't. I guess I won't
be getting those.
[/quote:7d74e1de30]
In glasses, "UV coatings" aren't yellow.
-MT |
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| Dan Abel... |
| Posted: Wed Oct 14, 2009 12:06 pm |
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In article <6fKdnZNwwssofUjXnZ2dnUVZ_sydnZ2d at (no spam) giganews.com>,
"Mike Tyner" <mtyner at (no spam) mindspring.com> wrote:
[quote:a33ca1afdd]"Liz" <fraternobombus at (no spam) yahoo.com> wrote
However, I still feel that an IOL should block most light below
400 nm, just for health reasons, and many don't. I guess I won't
be getting those.
In glasses, "UV coatings" aren't yellow.
[/quote:a33ca1afdd]
ObThreadDrift: Why are "shooting glasses" yellow? Is it to make the
light more monochromatic, and thus sharper?
--
Dan Abel
Petaluma, California USA
dabel at (no spam) sonic.net |
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| Mike Tyner... |
| Posted: Wed Oct 14, 2009 4:26 pm |
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Guest
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"Liz" <fraternobombus at (no spam) yahoo.com> wrote
[quote:bd572d4ffc]OK. But... I don't understand. How does that relate to what we were
just talking about?
[/quote:bd572d4ffc]
I thought you were saying you'd avoid the UV-blocking IOLs because they were
yellow.
-MT |
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| Mike Tyner... |
| Posted: Wed Oct 14, 2009 4:27 pm |
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Guest
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"Dan Abel" <dabel at (no spam) sonic.net> wrote
[quote:215f9475b3]ObThreadDrift: Why are "shooting glasses" yellow? Is it to make the
light more monochromatic, and thus sharper?
[/quote:215f9475b3]
Yes.
And atmospheric scatter is blue-ish.
-MT |
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| Liz... |
| Posted: Wed Oct 14, 2009 6:13 pm |
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[quote:b70b90260e]I thought you were saying you'd avoid the UV-blocking IOLs because they were
yellow.
[/quote:b70b90260e]
Sorry, I wasn't coherent. You're right, I hate the yellow.
1) Most of the yellow ones do block UV (defined by Liz as "<10% at
400nm"  .
2) Some of the clear ones also block UV.
3) Some of the clear ones block UV poorly.
4) Some of the clear ones block UV *very* poorly.
A few of the yellow ones also block UV poorly or very poorly.
As you point out, the UV-blocking chemical need not be yellow;
otherwise #2 couldn't exist.
I was wandering, and was so fascinated with those yellow human lenses
(don't they look like "toenail" seashells? They DO!) that I forgot my
point, which was to complain that if one wants #2 above, in an
aspheric, in a brand that any doctor actually uses, one's options are
apparently limited to silicone. FWIW.
I realize this isn't what the last post said!
cheers,
Liz
w. ADD in Indy |
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| Dr Judy... |
| Posted: Thu Oct 15, 2009 8:50 am |
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Guest
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On Oct 15, 12:13 am, Liz <fraternobom... at (no spam) yahoo.com> wrote:
[quote:a3cdcdb57d]I thought you were saying you'd avoid the UV-blocking IOLs because they were
yellow.
Sorry, I wasn't coherent. You're right, I hate the yellow.
1) Most of the yellow ones do block UV (defined by Liz as "<10% at
400nm" .
[/quote:a3cdcdb57d]
The yellow ones are blocking some blue light as well as UV, that is
why they look yellow. I think the confusion here is that the visible
spectrum is defined as wavelengths over 380mm and UV is defined as
wavelengths under 400, so there is an overlap of blue/violet light in
both groups.
Judy |
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| Liz... |
| Posted: Fri Oct 16, 2009 7:45 am |
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[quote:33d364deb2]Sorry, I wasn't coherent. You're right, I hate the yellow.
1) Most of the yellow ones do block UV (defined by Liz as "<10% at
400nm" .
The yellow ones are blocking some blue light as well as UV, that is
why they look yellow. I think the confusion here is that the visible
spectrum is defined as wavelengths over 380mm and UV is defined as
wavelengths under 400, so there is an overlap of blue/violet light in
both groups.
[/quote:33d364deb2]
My concern is that wavelengths from 380 - 400 are damaging to the
retina, and that many IOLs let most of this light through. If I were
to get any of those IOLs, I'd probably need UVA-blocking spectacles
outdoors, even during overcast conditions when the sun is not out and
when regular sunglasses would be too dark.
I have no idea what such glasses would look like, or cost, or where to
find them.
Anyone?
thanks,
Liz
Indiana |
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