Ah, so. A clear case of a cure waiting for a disease. A dream made on Madison Avenue.Originally Posted by kcount
Ah, so. A clear case of a cure waiting for a disease. A dream made on Madison Avenue.
Your Welcome. Wouldn't it be something if exposure to uv/hev/blue light at a young age becomes part of a high myopia prevention program?
Science is a way of trying not to fool yourself. - Richard P. Feynman
Experience is the hardest teacher. She gives the test before the lesson.
Ha, that would be very interesting. That definitely would go against blocking blue light willy-nilly.
Think about this: William Crookes, over 100 years ago, empirically uncovered the benefit that blue tinted lenses gave for reading comfort, aka Crookes A. Blue light, because of its shorter wavelength, can actually reduce accommodative demand, particularly for close-focus mobile device users and accomodative asthenopes.
B
I don't think that's correct. The original Crookes A was a clear lens that absorbed more UV than other glass of the day. Blue tinted lenses have no place in ophthalmic practice as far as I'm concerned because they let in all the bad blue and absorb all the good lower energy wavelengths. Blue tinting reduces accommodative demand? Not. Blue is scattered in the eye and makes accommodation much more difficult, ergo stressed and pushed.
Blue tinted lenses have no place in ophthalmic practice as far as I'm concerned
...............this discussion dated in 2006:
http://www.optiboard.com/forums/show...elvetlite-tint
in the eye, the dioptric interval defined by the wavelength range from 400nm-780nm is 2.5 diopters. The emmetropic monochromatic response of the eye is 572nm. So me thinks that yes, blue or blue filtered light can reduce accomodative demand for most individuals.
B
Last edited by Barry Santini; 02-10-2016 at 09:17 AM.
Me too. (Although seltzer down my pants would be a novel sensation.)
That's pure crap.
Maybe it's just confusion between electromagnetic wavelength (nanometers) and refractive power (diopters, focal lengths, etc).
Surprising confusion coming from an optician.
Don't hold back. Tell him how you really feel.
I just thought I would post this. Read the whole study if you wish. Draw your own conclusions......
Widespread use of computer and mobile technologies changed the exposure of human eyes to light. Despite public health concerns that staring at devices putting out high amounts of the blue light wavelength could damage human retinas, a recent study finds that most devices put out less of that light than the blue sky on a clear day. Claims that light sources with emissions containing blue light may cause eye damage raise were refuted by this study. A number of sources were assessed and the exposure conditions were compared with international exposure limits, and the exposure likely to be received from staring at a blue sky. None of the sources assessed approached the exposure limits, even for extended viewing times. The authors warn that the amount of light that gets transmitted from the surface of the eye to the retina is age-related, so children may be more sensitive to blue light. Light sources that are comfortable for adults could be distressing for children. The U.K. study did not look at other questions regarding the effect of blue light on human health, such as its potential to disrupt circadian rhythms and sleep. The study was published online in Eye on 15 January 2016.
Sorry you feel that way, drk. I happen to have the PP outlining this from Dr. Larry Thibos of IU School of Optometry, and that's EXACLY THE CRAP HE presented.
OK, a correction: 2 diopters
B
Last edited by Barry Santini; 02-08-2016 at 07:28 PM.
We sold UV protection for years on, well I'm pretty sure it helps protect your eyes. Some of the claims of these new product can be tested. But not by a bunch of ODs.
uhhhh, bunch of ODs? I think the ODs here are just about as puzzled as anyone else. Isn't it the lens manufacturers that are selling us this bill of goods? Could you explain your comment.
It's the conclusion that's specious, Barry. Don't write a giant piece in Lenses and Technology for Eyecare Business on it, please.
So think about it...yes, different wavelengths refract differently. I think Issac Newton figured that out.
But the contention that we "block blue light", that is, one of a zillion wavelengths we sense, in order to "compress the spectrum we're viewing" in order to "stabilize our accommodation" from "wandering around from trying to focus the blue light, then the green light, then the red light, then the blue light"..good heavens that's bull crap.
If minute changes in accommodation are so important, we'd better stop using handhelds...because...they're...moving!
The central point of Thibos's presentation is the emmetropia is a monochromatic concept. He devised an empirical experiment where the researchers uncovered that the Wavelength most closely associated with the eye'e subjective sense of sharpness is 572nm. Not 546. Not 587.
So longitudinal chromatic aberration will play a big role, both in the eye and out.
B
Last edited by Barry Santini; 02-10-2016 at 09:13 AM.
That doesn't mean a damn thing, clinically.
Why isn't there a problem with fluctuating accommodation, clinically, then? The same would apply at distance. "Hey doc. I'm getting 'eyestrain' when I'm looking at TV. It seems like I'm trying to accommodate those green parts of the football field. The NY Jets give me a headache, and the Redskins are blurry, somehow. But only when those teams play at home."
Never happens. Ever.
"Eyestrain". The bogey man of vision care. Ranked #2 to "glare".
The only reason I'm busting on you is:
1. You postulate like crazy
2. You have a big microphone
3. People listen to you
4. Monied interests publish what you think without peer review in trade rags
5. Monied interests would love to set you up as an expert that says "our blueblockers minimize eyestrain" says Barry Santini, BMOC.
Barry, there are monocular and binocular spatial clues to accomodation, and other cortical algorithms going on which far outweigh those couple of nanometers, IMHO, so while I may not agree with the way Dr. K is saying it, he's "probably" right. You might be technically right about the physics of it...but cortical functioning can negate that in a flash. So, I don't think chromatic aberration plays a clinically significant role in real-life accomodation. Did I do a scientific study to prove my theory? No.
Think about it:
The dioptric value of the lenses you test and prescribe with DOES NOT come close 'enough" to matching the dioptric value the eye desires. factor in exam distance (too close), mirrors/folding (even closer), and the premise that accomodation MUST never be present (fantastic for latent hyperopes?), and for mature adds, the inset of nuclear sclerosis, and my job is...tougher than it needs to be.
Anyway, it's really about the science here.
B
PS - I luv when you bust 'em. Keeps me honest...or at least in that direction, drk!
Last edited by Barry Santini; 02-09-2016 at 03:09 PM.
But what the eye "desires", or IOW the empirical refraction, may have little to do with what the visual cortex wants....
Just think hyperopes who are 20/50 at distance and say..."oh but I see fine at distance. I don't need glasses to drive" No way a few nanometers of blue light are going to affect his accomodative impulse....and it's not because my refraction is not "accurate". Real life is not accurate.
All I'm saying, Big B, is that you need to calm down a little. Your brain runs away with you too much. And then it gets codified in print.
Remember what Spiderman and Batman and Superman say: "With great power comes great responsibility".
I don't want patients asking me for "Crizal Prevencia with Accommorelax"!
And don't forget the scientific method, compared to the pseudoscientific marketing crap that we all have to endure.
Last edited by drk; 02-09-2016 at 10:54 PM.
Yeah, I'd hate to see the manufacturer's advertising "a lens that will make your accomodation more relaxed" because it filters blue light...kinda the way I hate those Gunnar? lenses are advertised as better for near and they sneak in a .375 add.
We tell our patients "more light" for reading. If more light makes reading easier, which I can attest to, than no tint would help accommodation. When I'm trying to put a black screw in black eyeglasses I don't grab a pair of tinted glasses. I turn on my desk light and throw on readers.
What is reality but a concept unique to each of us? Can anything be classed as real when our perceptions differ greatly on so many things? Just because we see something a particular way does not make it so.
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