Unconscious sight

May 16, 2012 11:19 AM

Did you know that the blind can see? And that's not even the most interesting part.

Did you know the sighted can see what they can't see? We have receptors for light (mostly blue) that bypass our consciousness and route deep into our brains (mostly the thalamus). And this 'second sight' has a hand in what we experience every day, from eye-dilation to migranes, and, significantly, the brain’s sleep circuitry and the body's circadian rhythms.

posted by brenton (24 comments total)

This is pretty nifty!

I have a friend who is blind. She did not sleep well when she visited Alaska some years back, during Midnight Sun, and complained mightily about it. She'll likely find this fascinating.
posted by MissySedai at 11:34 AM on May 16, 2012 [4 favorites]

This is incredible!

I'm wondering whether the use of blue lights can eventually be learned by blind people to provide a number of visual stimuli even though they can't detect images. Not sure how to apply that, but I can imagine it would be good for blind people to be able to tell whether a signal light were on or not.

Fascinating!
posted by darkstar at 11:41 AM on May 16, 2012 [1 favorite]

It's a tiny percentage of blind people who have the receptors ("About 5% of blind people who lack rods and cones in their eyes, still have functional blue light sensitive ganglia and their eyes can perceive light needed to set the body’s clock."), but it is still absolutely fascinating!
posted by dirtdirt at 11:48 AM on May 16, 2012 [4 favorites]

These neurons are now known to extend into the thalamus, a region of the brain known for promoting awareness. Presumably they deliver some kind of essential information there. When neuroscientists find out what kind of message it is, they will make real progress—perhaps toward fighting pain, and definitely toward getting a better look at our secret selves."

Or perhaps they keep us from turning into zombies.

Cool article. The blue light thingy was neat--makes you wonder if you could rig up a room with objects emitting varying intensities of blue light that could allow rod-and-cone-blind people to "see"?
posted by resurrexit at 11:55 AM on May 16, 2012 [1 favorite]

I wonder if this ties in with season affective disorder and light box therapy.
posted by rmd1023 at 11:56 AM on May 16, 2012

*that is, "rod-and-cone-blind people" with those irRGCs or whatever they are.
posted by resurrexit at 11:56 AM on May 16, 2012

That should means that if I filter out blue light in my house, I could change my circadian rhythms. It seems like there should be some niche to fill there of people who live way up North or work nights that need light and a way to change their sleep cycle or something.

Maybe places that are open 24-hours could emphasize the blue spectrum at night to help their workers feel more awake too.
posted by VTX at 11:58 AM on May 16, 2012

>I wonder if this ties in with season affective disorder and light box therapy.

It totally does! I actually am changing the theme on my browser and computer to a blue one, and I'm adjusting my whole monitor a little towards the blue. I already have a wake-up light that emits blue frequencies, but I am guessing blue throughout the day will help avoid that 3pm tiredness.
posted by brenton at 11:59 AM on May 16, 2012

If the blind can see, I owe my neighbor an apology.
posted by orme at 12:03 PM on May 16, 2012 [4 favorites]

Metafilter: I am guessing blue throughout the day will help avoid that 3pm tiredness.

You guessed wrong buster!
posted by howfar at 12:04 PM on May 16, 2012 [4 favorites]

My lab studies this stuff. This is just the tip of the coolness iceberg when it comes to this AMAZING field. If I have time later (gotta go to a seminar) I'll post some cool links.
posted by Cygnet at 12:10 PM on May 16, 2012 [3 favorites]

Cygnet - please do post more info. This sounds fascinating.
posted by tdismukes at 12:28 PM on May 16, 2012

Thanks for this - maybe the orange lamps and eyeglasses (https://www.lowbluelights.com/) will help with delayed phase sleep disorder.

The morning light box is recommended for just after I naturally awake, but I almost never get to sleep that long.
posted by yath at 12:29 PM on May 16, 2012 [2 favorites]

Great post, thank you!
posted by Lynsey at 12:35 PM on May 16, 2012

This is exactly the kind of thing I'm raving on madly about when I say that we still haven't discovered/quantified all of our senses.

Not in a woo woo ESP spoonbending kind of way, but in a we're fantastically complex and sensitive and we're still learning new things about ourselves kind of way.

Technically all of our skin is photosensitive. The rods and cones in our retinas are just extremely specialized skin cells.
posted by loquacious at 1:09 PM on May 16, 2012

Not in a woo woo ESP spoonbending kind of way

Of course not, there is no spoon...
posted by VTX at 1:11 PM on May 16, 2012

brenton, and anyone else who needs to adjust your monitor: if you haven't already, try F.lux. Many, many happy people rave about it changing their lives by helping them sleep.
posted by RikiTikiTavi at 1:14 PM on May 16, 2012 [8 favorites]

As a person who has migraines triggered by fluorescent lights, be they CF or the long tube fluorescents, I dread the day when incandescent is completely outlawed. Even when fluorescent bulbs are encased in a orange-ish cloudy light shade, it still hurts to look at them.

As more of this research comes out, it makes me less afraid to speak up about the problem and more hopeful that continued research will drive folks to make new lighting that is mammalian eye & brain friendly.
posted by msjen at 1:52 PM on May 16, 2012 [1 favorite]

On the plus side, msjen, LED lights are already making inroads into the consumer market. I bought my first LED nightlight a few months back. Less than half a watt and it provides enough illumination to keep the whole stairway lit and safe.
posted by darkstar at 2:03 PM on May 16, 2012

If I have time later (gotta go to a seminar) I'll post some cool links.

Dude, this is your thing!

1 Skip the seminar
+2 write a ridiculously long comment (with cool anecdotes)
+3 ???
= Sidebarred!
posted by resurrexit at 2:20 PM on May 16, 2012 [1 favorite]

"surgically removed the eyes of the mice"

Is it just me or did anyone else freak out about these scientists and their "sciency" ways.
posted by greenhornet at 8:11 PM on May 16, 2012

Does that monitor adjustment thing really make a difference?

I wonder how this unconscious sight stuff is related to those people who can see more of the spectrum than regular humans. (My doctors as a kid always thought I was one of them.)
posted by These Birds of a Feather at 9:14 PM on May 16, 2012

Yeah I felt pretty bad for the mice.
posted by Apocryphon at 12:29 AM on May 17, 2012

"surgically removed the eyes of the mice"

Is it just me or did anyone else freak out about these scientists and their "sciency" ways.
posted by greenhornet

Kept me from even thinking about trying to be any kind of biologist.

If they're just scraps of tissue you can do anything you want with, so are we.
posted by jamjam at 4:33 PM on May 17, 2012