SAD and blue-blocking IOLs

Many IOLs now have a slight amber tint - supposedly they block UV and
some percentage of visible light up to 450 nm. This is some visible
blue.
With the recent discovery of how the human circadian clock is set by
blue light entering the eyes, and how the setting relates to seasonal
affective disorder, I wonder if these IOLs might alter that
process.
I'm sure it's somewhere on the web.

cheers,
Liz
(who gets SAD starting in Sept., here at 40 N)

I got a little info.

It appears that the yellow filtering on the Alcon SN60WF is designed
to mimic the transmittence of the human (biological) lens.

This tinting *should*, then, be OK for the sensors inside the eye that
set the body's circadian clock to be able to receive the range of blue
light they require to avoid depression. According to various web
sites, that range is roughly 425-470 nm, which is nearly exactly what
the IOL also blocks, to varying percentages.

It does seem counterproductive to buy a blue-light-emitting lightbox
to treat one's SAD, paying extra for those devices that put out MORE
and STRONGER light, and then to implant an IOL that blocks about 50%
of this same light.

(Maybe Alcon could make a clear aspheric and market it as an "anti-
depression" lens.)

Anyone know more about this?

Liz
Indy

> I haven't studied SAD for several years, but I recall there was evidence
> that light therapy for SAD was effective on the skin as well as through the
> eye. One report I read favored the backs of the knees, of all things.

I remember this study, but not what it said. Have to dig it up
again.
I think the eye pigment sensors must work better, or people would be
shining light on their skin...?

I guess tomorrow I'll be calling labs that research SAD. I often
wonder if older people have more depression if their lenses get more
opaque with age.

I'm sure all this is on the web, I just get sick of hunting for stuff.

cheers,
Liz
Indy

In article
<f2c91499-0664-4882-b622-(E-Mail Removed)>,
Liz <(E-Mail Removed)> wrote:


> I guess tomorrow I'll be calling labs that research SAD. I often
> wonder if older people have more depression if their lenses get more
> opaque with age.

Well, of course they get depressed. Going blind is a very depressing
thing. It's not called SAD, of course, it's just called blindness.

I used to get depressed about the rain in Seattle. That wasn't SAD,
either, and I was young (18-22, going to college). I like to walk
around outside, but I don't like walking in the rain. So, when it
rained, I spent more time cooped up inside. I don't like that. I was
happy to leave Seattle for a couple of reasons, one being the weather.
The other was that there were no jobs when we graduated from college in
1972. There had been massive layoffs. Billboards said, "Will the last
person leaving Seattle please turn out the lights".

--
Dan Abel
Petaluma, California USA
(E-Mail Removed)

Found it!! The study that showed that light on the back of the knees
could reset the circadian clock was duplicated, and the second time no
effect was shown.
So I think this skin effect is not believed anymore. I think if you
lose your eyes, you can no longer reset your clock.

> > I often wonder if older people have more depression if their lenses getmore
> > opaque with age.
>
> Well, of course they get depressed. *Going blind is a very depressing
> thing. *It's not called SAD, of course, it's just called blindness.

No, I mean that long before they go blind, I think their lens begins
to block more of the blue light, such that perhaps this affects their
mood.

> I used to get depressed about the rain in Seattle.

I believe you!!

>That wasn't SAD, either, and I was young.

But that's the point. Dim light leads to SAD **and** depression.
If the light is dim because it's cloudy, or if it's dim because your
lenses are blocking more blue as you age, those are both possible
causes.

*>Billboards said, "Will the last person leaving Seattle please turn
out the lights".

I wish this were funnier than it is. We're sinking fast in Indiana
too.

Liz
Indy

In article
<0dae0a6c-a93a-4d9a-b368-(E-Mail Removed)>,
Liz <(E-Mail Removed)> wrote:


> No, I mean that long before they go blind, I think their lens begins
> to block more of the blue light, such that perhaps this affects their
> mood.

It's a well know effect (although I don't know if it hits everybody)
that cataract makes everything turn yellow, including all the pretty
green plants. One of the things that made me happy after my cataract
surgery, was seeing green plants, including green grass. I'm pretty
sure (but I'm no optical or eye expert) that the way everything turns
yellow is by blocking the blue light. I never tied this to SAD, but I
was certainly happy to get green back.

My father has some SAD. He lives up north, and the days get very short
in the dead of winter. Sometimes the sun barely comes out, although it
gets light. I grew up there, and I remember going sledding after
school. I could only go for about an hour before it got too dark and I
had to go home.

--
Dan Abel
Petaluma, California USA
(E-Mail Removed)

On Sep 24, 3:17*am, Liz <fraternobom...@yahoo.com> wrote:
> Many IOLs now have a slight amber tint - supposedly they block UV and
> some percentage of visible light up to 450 nm. *This is some visible
> blue.
> With the recent discovery of how the human circadian clock is set by
> blue light entering the eyes, and how the setting relates to seasonal
> affective disorder, I wonder if these IOLs might alter *that
> process.
> I'm sure it's somewhere on the web.
>
> cheers,
> Liz
> (who gets SAD starting in Sept., here at 40 N)

Re: Blue-light blocking IOLs

I studied this issue before getting Alcon's amber IOLs implanted in my
own eyes. The purpose of Alcon's blue-light blocking feature was to
provide protection against age-related macular degeneration. The
basis for this "protection" was weak correlational evidence, which was
not supported by subsequent research. I actually wondered if this
"special feature" was something dreamed up in Alcon's marketing
department to get an edge on their competitors. On the other hand, I
could find no credible anywhere that this feature that had any
negative effects whatsoever. The IOLs did not affect my perception of
colors, sleep patterns, or mood. If you're really concerned, AMO's
aspheric Tecnis IOLs don't have this feature.

I was right!
Found many mentions on the web that people's lenses normally do get
yellower as they age, even without cataracts, and that this does, or
might, or does not (I'm not convinced which yet) affect your ability
to reset your clock via blue light and thereby avoid SAD and
depression.
More than that, it's a mess. I found arguments that the amber-tinted
IOLs might protect against AMD; that amber-tinted IOLs do (or don't)
impair night vision; that amber-tinted IOLs can be expected to (or
should not be expected to) decrease one's ability to respond to
circadian cues.

A whole article on this topic turned out to be authored entirely by
three docs who are consultants for three IOL companies.
:-(

I need to find a lab with people who study SAD and circadian rhythm.
They'll know if this concern is real or insignificant.
A relevant question that might actually have been investigated would
be whether older people, with intact but yellowing biological lenses,
which probably resemble the tinted IOLs, have more trouble resetting
their body clocks.

on the trail,
Liz in Indy

>cataract makes everything turn yellow,


Yes.


> [think] that the way everything turns yellow is by blocking the blue light.


Yes.


> I never tied this to SAD,


The info on blue light and SAD is fairly recent.


> My father has some SAD. He lives up north, and the days get very short
> in the dead of winter.


Yes, I lived near Chicago for 30 years. The light (and cold) affect
me deeply.


>I studied this issue before getting Alcon's amber IOLs implanted in my
own eyes. The purpose of Alcon's blue-light blocking feature was to
provide protection against age-related macular degeneration.


Yes.


>basis for this "protection" was weak correlational evidence, which was
not supported by subsequent research.


It seems the question is still open. Not surprising, since it would
be hard to prove.


> On the other hand, I could find no credible anywhere that this feature that had any negative effects whatsoever. The IOLs did not affect my perception of colors, sleep patterns, or mood.


Did you have depression before? (I mean if this isn't too personal to
ask.)


I'm also concerned that amber is said to impair night vision to some
degree. Did you notice this?


I guess almost anything would be better than what you see with the
cataract in! However, I've heard so frequently that people can't
drive at night after cataract surgery that I'm starting to wonder if
there is something going on about that.


thanks,
Liz




Re: Blue-light blocking IOLs

I studied this issue before getting Alcon's amber IOLs implanted in
my
own eyes. The purpose of Alcon's blue-light blocking feature was to
provide protection against age-related macular degeneration. The
basis for this "protection" was weak correlational evidence, which
was
not supported by subsequent research. I actually wondered if this
"special feature" was something dreamed up in Alcon's marketing
department to get an edge on their competitors. On the other hand, I
could find no credible anywhere that this feature that had any
negative effects whatsoever. The IOLs did not affect my perception
of
colors, sleep patterns, or mood. If you're really concerned, AMO's
aspheric Tecnis IOLs don't have this feature.

Almost all the research on IOLs is sponsored by the lens
manufacturers. That says a lot. When Alcon's blue-light filtration
feature was first introduced, their paid consultants wrote dozens of
articles about the alleged benefits of this new feature. AMO's paid
consultants countered with unsupported allegations that the yellow
IOLs would impair color perception and negatively affect sleep
patterns and mood. It would not have been difficult for the AMO
consultants to design studies to back up their allegations, but I'm
not aware of any such research being carried out.

One rather strange aspect of Alcon's IOLs is that the amount of blue-
light filtration varies with the power of the IOL. Powers used to
correct very farsighted eyes have the most blue-light filtration (and
the most intense yellow color); those used to corrected very
nearsighted eyes have the least. I'm in the latter group (where
there's not a whole lot of filtration going on). I did not suffer
from depression before I got my AcrySof IQs, and my mood didn't worsen
afterwards.

There are very good aspheric monofocal IOLs made by Alcon, AMO, and
Bausch & Lomb (whose IOLs block violet light). You can learn more
about the benefits of an aspheric IOL by watching the patient
education video at www.tecnisiol.com. (I believe that the same
benefits would apply to any aspheric IOL, not just the Tecnis.) So if
you have concerns about blue-light filtration, by all means get Tecnis
IOLs.