[sigil]

What an interesting experiment. Could there be some basis, after all, to the urban legend that eating carrots improves night vision? Carotenes are "partly metabolized into Vitamin A" [1], but this experiment is skipping the precursors and going straight for what I assume are large and exclusive doses of Vitamin A. Can it really be that no one has tried this before?

Related and probably equally silly idea: I've always wanted a pair of sunglasses that could tune in to different EM spectra. How far are we from that? Night vision goggles are bulky because they need external power to do the frequency shifting, right?

[1] http://en.wikipedia.org/wiki/Carrot#Nutrition

[wisty]

The urban legend was mostly due to its use in WWII, to explain why the allied night fighters were so good. The fighters actually used radar, which was still top secret.

[dingle_thunk]

Yeah it's a consideration, but the mere use of an existing old wive's tale doesn't completely discount the possibility of there being some truth to it anyway...

[dredmorbius]

Source?

[27182818284]

"Much publicity has been given to the good effects of carrots on night vision and some newspapers have even begun to use the vegetable as a nickname for certain ace pilots. Actually, night-fighter pilots don't eat anymore carrots than day fighters do..." —LIFE June 23, 1941

(Not quite the same, but in a similar vein)

[dredmorbius]

Thanks. Snopes has this:

http://www.snopes.com/food/ingredient/carrots.asp

"While carrots are a good source of vitamin A (which is important for healthy eyesight, skin, growth, and resisting infection), eating them won't improve vision. The purported link between carrots and markedly acute vision is a matter of lore, not of science. And it's lore of the deliberately manufactured type.

"In World War II, Britain's air ministry spread the word that a diet of these vegetables helped pilots see Nazi bombers attacking at night. That was a lie intended to cover the real matter of what was underpinning the Royal Air Force's successes: Airborne Interception Radar, also known as AI. The secret new system pinpointed some enemy bombers before they reached the English Channel.

"British Intelligence didn't want the Germans to find out about the superior new technology helping protect the nation, so they created a rumor to afford a somewhat plausible-sounding explanation for the sudden increase in bombers being shot down. News stories began appearing in the British press about extraordinary personnel manning the defenses, including Flight Lieutenant John Cunningham, an RAF pilot dubbed "Cats Eyes" on the basis of his exceptional night vision that allowed him to spot his prey in the dark. Cunningham's abilities were chalked up to his love of carrots. Further stories claimed RAF pilots were being fed goodly amounts of this root vegetable to foster similar abilities in them...."

That's an interesting form of disinformation. I've been known to employ somewhat similar tactics myself.

[Scoundreller]

> I've been known to employ somewhat similar tactics myself.

How can we be sure?

[dredmorbius]

The context involved a disagreement with someone else which grew to include a legal action.

Turns out I'd managed to access a significant trove of documents, admissible in court, strongly supporting my side's case.

I was in communication with several entities I suspected were communicating (directly or otherwise) with the opposing side, and while it was useful to communicate that we had significant information, detailing just what it was, or how it was obtained, was somewhat less so.

So the cover story we worked out was that we had deep connections to the black-hat online hacker community who were able to pull all kinds of random information out of the Net. Playing up the whole hacker mistique thing.

One consequence of this was opposing counsel strongly suspecting that the evidence we introduced wasn't admissible. They were rather surprised when it turned out to be very admissible. The fact that the opposing side's witnesses were shown to be markedly less than credible didn't help their side (and may have sabotaged their own case).

It was a vaguely satisfying aspect of an otherwise fairly unpleasant episode.

[Sami_Lehtinen]

AFAIK vitamin A is poisonous in larger doses. In Finland they were worried at time that people might be getting to much of vitamin A. http://en.m.wikipedia.org/wiki/Hypervitaminosis_A

[possibilistic]

Everything is poisonous at some dosage.

http://en.wikipedia.org/wiki/Median_lethal_dose

Edit: From this [1] non-scholarly source,

    "The median lethal dose (LD50 value) of vitamin A injected intramuscularly 
    in a water-miscible form in the young monkey is 0.6 mmol (168 mg) retinol/kg 
    body weight. Extrapolated to a 3-kg child and a 70-kg adult, the total LD50 
    dose would be 1.8 mmol (500 mg) and 41 mmol (11.8 g) respectively."

Also, it's teratogenic. Just like an innumerably many other chemicals we ingest daily.

[1] http://www.uta.edu/faculty/sawasthi/Lecture%20Notes%20Chem14...

[mnw21cam]

Hence why Isotretinoin (http://en.wikipedia.org/wiki/Isotretinoin) is a restricted drug in many countries, although it is a vitamin A-like chemical that is used to clear up very severe acne. Women who are prescribed the drug in the UK have to provide proof that they are on a reliable form of contraception and are not pregnant when they collect each month's worth of pills. It causes severe birth defects.

[WhoBeI]

Night vision uses the photoelectric effect to translate a few photons from the lens into a picture you can see. It doesn't change the frequency of incoming light - it absorbs it and transmits an electron. Basically you are carrying around something similar to an old style tv on your head.

[possibilistic]

Photoreceptor proteins, such as rhodopsin (typically the first GPCR [1] you'll study in a biochem undergrad program), each have different characteristic absorption spectra. But it's much more complex than that--each of these proteins exhibit different absorption spectra given different isomerizations and even different conformers [2] .

Here are some absorption spectra [3] of crystals of various rhodopsin isomers. I'm not sure if any of these are biologically relevant isomers, but it's interesting that these were not in solution. (I suppose that since they're membrane-bound GPCRs and might be difficult to study in solution? This isn't my field of study.)

Check out some bacterial absorption spectra [4]. Visual perception isn't limited to organisms with eyes. Or even eukaryotes, for that matter. It's actually pretty ancient [5].

On that note, pigment chemistry is pretty fascinating.

1. http://en.wikipedia.org/wiki/G_protein-coupled_receptor The GPCR family is really cool. A ton of our sensory perception arises from class A GPCRs. Here's a really beautiful diagram of the 7 transmembrane regions of rhodopsin: http://physrev.physiology.org/content/physrev/81/4/1659/F1.l...

2. http://www.sciencedirect.com/science/article/pii/S2210271X13... Just to cite an instance, though this one isn't vision-related.

3. http://www.pnas.org/content/103/44/16123/F1.expansion.html

4. http://group.szbk.u-szeged.hu/ormosgroup/abs/abs.html

5. http://en.wikipedia.org/wiki/Archaearhodopsin

[spingsprong]

The Japanese by contrast never developed truly effective airborne radar during WW2, so actually did select the pilots with the best night vision to fly their night fighters.