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Question about blue light and red tinted glasses

Question about blue light and red tinted glasses - Physics Forum

Question about blue light and red tinted glasses - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 01-30-2005, 01:04 AM
Christopher M.
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Default Question about blue light and red tinted glasses



What effect does wearing red-tinted glasses have on protecting the eyes from
high energy visible light (e.g. blue light)?
As blue light passes through the lense is it's wavelength changed so it
becomes red light?
Or does the red tint eliminate or reduce the blue light?

Thanks.


W. Pooh (AKA Winnie P.)
"Don't eat soup! Soup makes you poop!"
--Baron von Stinkipantz


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  #2  
Old 01-30-2005, 01:42 AM
tadchem
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Default Question about blue light and red tinted glasses


"Christopher M." <[Only registered users see links. ]> wrote in message
news:JoWKd.2560$3U3.2347@trndny06...
from

The blue light doesn't get through at all.

The blue visible light is harmless. The danger is in the UVB radiation (the
higher energy part of the UV band).

There is evidence that UVA radiation is essential to synchronizing the
circadian clock and to overcoming the adverse effects of jet lag and
"seasonal affective disorder" (aka SAD).

Lenses that are tinted yellow, brown, or amber absorb blue light and enhance
contrasts in haze or fog:
[Only registered users see links. ]

The principle result of using red-tinted lenses is that the blue-sensitive
cells in the retina are not desensitized by light. They actually respond to
all visible colors EXCEPT red, to some measurable degree. The
blue-sensitive cells are the most sensitive and useful for peripheral vision
and dark vision, so protecting them from light allows rapid adaptation to
sudden darkness.

At one time (I am not sure if the practice is still performed) submarines
used red interior lighting at night so that if the ship had to surface in
total darkness the crew could see immediately. A delay of several minutes
in adjusting the eyes to darkness could be disastrous.


Tom Davidson
Richmond, VA



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  #3  
Old 01-30-2005, 01:49 AM
N:dlzc D:aol T:com \(dlzc\)
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Default Question about blue light and red tinted glasses

Dear Christopher M.:

"Christopher M." <[Only registered users see links. ]> wrote in message
news:JoWKd.2560$3U3.2347@trndny06...

It tends to absorb the blue light. How effective it is, depends on the
lens-system.


Sometimes, yes. If the lens is occularly true (images appear clear, if
colored red), then it is possibly not as protective as you'd hope. If the
lens gets direct irradiation from the intense blue light source, it is
possible:
- the intensity of red will be (much) higher, or
- the red material will fail and the blue will get through.


"Attentuate" might be a better word. "White" LEDs are commonly a blue LED
and material that absorbs blue and reradiates at all different wavelengths.

During WWII, older people, that had their corneas removed, were used to
detect UV-signals between shore and ship.

David A. Smith


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  #4  
Old 01-30-2005, 02:30 AM
ošin
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Default Question about blue light and red tinted glasses

> What effect does wearing red-tinted glasses have on protecting the eyes

Visible blue light is not really harmful, so the eyes do not need protection
from it. Ultra violet (UV) is a danger though. The effect of red-tinted
glasses on UV light cannt be answered, since it depends on the material.
Most likely, it will absorb the UV to some extent, giving some protection.
But It may not. It could even make problems worse by causing your iris to
open more due to lower luminance in the visible range. It is possible for a
material to transmit only red and UV, making it appear red-tinted, and also
transparent to UV. Yikes!


No. Wavelegth does not change as it is transmitted.


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  #5  
Old 01-30-2005, 05:11 AM
Christopher M.
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Default Question about blue light and red tinted glasses

"tadchem" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
(the

"The Schepens Eye Institute reports that 'the blue rays of the spectrum seem
to accelerate AMD [age-related macular degeneration] more than other rays of
the spectrum.'"
[Only registered users see links. ]


W. Pooh (AKA Winnie P.)


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  #6  
Old 01-30-2005, 09:38 PM
tadchem
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Default Question about blue light and red tinted glasses


"Christopher M." <[Only registered users see links. ]> wrote in message
news:c0_Kd.4419$zP5.3655@trndny09...
seem
of

Your source for this is not the Schepens Eye Institute itself, but an
alleged non-profit organization (the American Macular Degeneration
Foundation) that is in fact fronting for two commercial interests:
the Specialty Lens Corp.
[Only registered users see links. ]
and the Melanin Vision Center
[Only registered users see links. ]
both of which are peddling 'melanin' lenses to keep the blue light out of
your eyes.

Go to the original source:
[Only registered users see links. ]
About half-way through their FAQ is the statement:
"Smoking, diet, and genetics appear to be factors that contribute to the
risk of getting AMD."
There is no mention of 'blue' on the page.

Likewise there is no mention of 'blue' in their AMD brochure:
[Only registered users see links. ]

The Schepens Eye Institute has been informed of the situation.

I would be fascinated to see the experimental protocols (controls,
monitoring apparatus, sample selection protocols, etc.) used to establish a
vague conclusion such as 'the blue rays of the spectrum seem to accelerate
AMD more than other rays of the spectrum' *without* resorting to
experimentation on human subjects that leads to exacerbation of an incurable
disability.

You could learn to be more skeptical of unsupported claims.


Tom Davidson
Richmond, VA


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  #7  
Old 01-31-2005, 11:17 PM
Christopher M.
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Posts: n/a
Default Question about blue light and red tinted glasses

"tadchem" <[Only registered users see links. ]> wrote in message
news:[Only registered users see links. ]...
a
incurable

Here's a study:

LIPOFUSCIN IN AGING AND
MACULAR DEGENERATION
(BIOPHYSICS,
CLINICAL OPHTHALMOLOGY)
"Excessive accumulation of lipofuscin [fatty deposits] in the
lysosomes [disposal center for the cell] of retinal pigmented epithelium
[the outermost layer of cells of the cornea]
(RPE) cells may impede the metabolic activity
of these cells and has been shown to act
as a photosensitizer, generating free radicals.
Furthermore, one of the components of lipofuscin,
the fluorophore A2-E, has been shown
to inhibit lysosomal digestion of protein,
cause disruptions of lysosomal membranes,
and initiate ***blue-light***-induced apoptosis [programmed cell death] of
RPE cells".
These mechanisms are thought to
play a role in pathogenesis of age-related
macular degeneration (AMD) and juvenile
macular degeneration.
Noninvasive fluorospectrometry and fluorescence
imaging have been used to study the
biological consequences of lipofuscin accumulation
in normal subjects during aging, and
in patients with AMD or juvenile macular
degeneration.
Our results showed that lipofuscin
increases with age in normal subjects,
reaching highly variable levels at mid-life.
Factors associated with increased (age,
smoking) and decreased (vitamin supplementation,
dark iris) risk for AMD were also
significantly correlated with increased or
decreased accumulation of RPE lipofuscin.
These results suggest that lipofuscin measurements
provide a cumulative index of
oxidative damage in the eye.
In patients with AMD we observed a significant
decrease in lipofuscin levels. The
decrease may be caused by chemicophysical
changes in lipofuscin at high concentrations,
causing it to lyse the lysosomes in which it is
trapped and/or by partial atrophy of RPE
cells. These findings are not inconsistent with
lipofuscin reaching high levels before disease
is initiated, and then falling. We are presently
investigating lipofuscin levels in patients with
the preclinical, earliest signs of AMD. In
patients with Stargardt's disease (fundus flavimaculatus),
lipofuscin levels are significantly
higher than normal, confirming histopathologic
findings. We use autofluorescence imaging
to study the lipofuscin distribution at pathological
sites such as drusen, hyperpigmentation,
and geographic atrophy."
[Only registered users see links. ] (PDF, 1.27MB)


W. Pooh (AKA Winnie P.)





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