Jump to content
UltravioletPhotography

UV sensitivity among mammals


Recommended Posts

Here, courtesy of the 27 February 2014 issue of NewScientist is a reference to a paper entitled "The spectral transmission of ocular media suggests ultraviolet sensitivity is widespread among mammals" DOI: 10.1098/rspb.2013.2995.

 

http://rspb.royalsocietypublishing.org/content/281/1780/20132995.full

 

quote from the abstract

 

.... Other mammals, such as hedgehogs, dogs, cats ferrets and okapis had lenses transmitting significant amounts of UV-A (315 - 400 nm) suggesting that they will be UV-sensitive even without a specific UV visual pigment.

 

Interesting....

 

Dave

Link to comment

I can see with the illumination of a UV black light & not just the fluorescence. Does that make me special or is it the person that can't see with the illumination of a UV black light that is special ?

Also we need reminding the there are insufficient levels of Solar near or long wave UV reaches the Earth's surface to be of much use.

Are these labs measuring UV transmittance of these mammals lenses with natural daylight or artificial light sources ?

Cheers

Col

Link to comment
A UV blacklight has strong sidebands in the visible blue, so no wonder you can "see" with it even though fluorescence is not emitted. Hopefully you did your observations through UV protective glasses?
Link to comment

Oh, I haven't been issued UV protective glasses when I have gone to the discos (long time ago, mind you) or seen any bank tellers wearing UV protective glasses when checking items under a UV black light ?

Thanks Bjorn, I wear eye glasses now, so they absorb harmful UV ?

Cheers

Col

Link to comment

All depends on the dose received which again is a function of source strength, distance to source, and duration. A disco is a complete different situation compared to doing UV work up close.

 

Ordinary glasses do transmit a tad less UV - easily seen as they photograph darker in UV.

Link to comment

Posted to another forum last august:

 

Normal human visual range, photopic response spectrum, is known to overlap the UV from about 385 - 400 nm. Older eyes see less of this overlap. nonUV blocking IOLs of course skew this to shorter non physiological wavelengths.

 

You might find this interesting (I did): http://neuronresearc...etrachromat.htm

 

(For full topic see: http://forum.mflense...ion-t59822.html)

 

- John

Link to comment

The ability to see UV is not really something you want to have. Take it from one who has had 3 eye surgeries on her left eye because of a double cataract at a rather early age. The eye surgeon was appalled by my confessed activities with UV flashes and UV torches even though I have UVEX goggles.

 

Note from below:

Around black lights, if you see bright blue-white light you might be seeing UV.

If you see purple, you're seeing associated visible sidebands.

Go to the second link for the best demo of what UV "looks like" to those who can see it.

 

Here's my Nikongear post on the topic:

 

Although rare, it is no news that some people can detect near-UV. Some youngsters or some folks without a lens in one or both eyes have this ability. A Colorado man, Alek Komarnitsky, discovered that after cataract surgery and implantation of a certain kind of Intra-ocular Lens in his eye, he could detect some near-UV. He has written his interesting story in the article linked below.

 

How can near-UV detection happen in the human eye? For some people, near-UV excites all of the R, G and B receptors with the Blue receptor being slightly more sensitive. So such folks will see the typical near-UV black light as emitting a bright, blueish-white light. When the rest of us look at a near-UV black light, we see only some Visible dark purple light. (Near-UV black lights emit wavelengths a bit past 400nm into the Visible spectrum.)

 

Some children, before the lens of the eye has begun to turn yellow-ish with age, can see this blueish-white UV glow. However, most of us do not have this capability when young. And if we do, it is rapidly lost with age. Because UV is extremely damaging to the eyes, it is probably for the best that our eyes' lenses become yellowish fairly early on and begin to block near-UV. By the time we are middle-aged, our lenses are blocking quite a lot of violet and some blue as well.

 

Alek Komarnitsky's well-illustrated story about his cataract surgery is linked here. The part about UV detection is down quite a ways. So if you want to skip directly to that, please use the second link. There is a nice mouse-over showing how he sees a near-UV black light and how it appears to the rest of us. I'm not sure what he is seeing in the black clothing demonstration, near-UV or UV-fluorescence.

 

READ Mr. Komarnitsky's entire cataract story here:

http://www.komar.org...ery-crystalens/

 

SKIP to Mr Komarnitsky's near-UV detection here:

http://www.komar.org...let-color-glow/

Link to comment

Dave, thank you for the link to the very interesting paper.

It has a nice list of references to other work too.

 

I love this stuff !!

Link to comment

Here's a link to "Trichromacy in Australian marsupials"

 

http://www.sciencedirect.com/science/article/pii/S0960982202007728

 

"We suggest that Australian marsupials have retained an ancestral visual pigment that has been lost from placental mammals"

 

Now... all we need is for someone to do microsurgery on the eyes of Australian insects and who knows what wonders will appear :unsure:

 

Dave

Link to comment

No worries Dave.....no need for the microsurgery.

I've got a bunch of critters here now, that I am training to nod or shake their heads, when I show them certain wavelengths.

Still training them though as sometimes they get mixed up with nodding & shaking, but by the time they start to get it right they expire :unsure:

Cheers

Col

Link to comment

col,

 

Too bad they die so quickly. You have them just to the point where they could be upstanding members of Parliament.

Link to comment
  • 2 weeks later...
Bill De Jager

The first post relates to this effect from high-voltage powerlines: http://onlinelibrary...cobi.12262/full . The effect can be viewed in videos: http://gizmodo.com/a...ight-1546394958 and http://www.independe...ye-9187631.html . While the journalism in the last two articles may be somewhat simplistic and sensationalistic, this looks like an issue that needs more research, and when more is known, action to reduce the problem.

 

These UV flashes could be an interesting subject for UV photography, especially at night.

Link to comment

Bill, thank you for these links. Quite interesting!

 

And yes we should try for a photograph. :D

Link to comment

Thanks Bill

I wonder what noise these UV auras make, perhaps out of our range but heard by the animals around them ?

Col

Link to comment

The 15 March 2014 issue of NewScientist contains a letter to the editor :

"Your item on ultraviolet vision (22 February, p 7) reminded me of the time I discovered I could see a little way into the ultraviolet.

In my first year at university, we were measuring the wavelengths of the spectral lines in the potassium vapour spectrum. I was taking much longer than the rest of the group, so the tutor come over to see why. He looked at my results and exclaimed "You can't see those!" So I lined up the spectroscope on three of the lines while he checked the textbook. "You're right," he admitted. "You're seeing ultraviolet".

In a long and very varied career since then, I have had many opportunities to check, and I can definitely see a short distance into the ultraviolet. It would be interesting to know if an other NewScientist readers can do this. I have met only two other people who have this ability."

Link to comment

Thanks for this Dave

And the obvious question not answered here is.....what wavelengths or emission lines can he see ?

Col

Link to comment
  • 3 weeks later...

This could go on for ever, in the 12 April 2014 issue of NewScientist was the following letter to the editor in response to the above:

"Three years ago I lost the sight in one eye because of septicaemia following a dog bite.

The vitreous humour was removed from my eye and replaced with silicone oil, restoring my vision immediately. Within six months, I developed a cataract and had to have a synthetic replacement lens. This restored the vision in the eye to a better standard than ever before.

The following evening, I went for a drink in my local pub, and noticed I could see the ultraviolet light of the counterfeit note detector behind the bar much more distinctly with the repaired eye than with the other.

Assuming that both my retinas are equally sensitive, I wonder whether during the course of evolution, Mother Nature has devised protection against UV light for our eyes that is not afforded by either silicone oil or a prosthetic lens."

 

You will no doubt have guessed by the reference to the local hostelry that the writer came from the UK, from Wales in fact.

 

Dave

Link to comment

Maybe what the Welsh guy was seeing was simply the visible purples that the typical blacklights also output? After cataract removal there is a restoration of the intensity of purples and blues, some of which have been blocked by a cataract and by the yellowed lens of an older eye.

 

With my good "new" lens-implanted eye I now see the sky as bluer than I see it with my "old" yellowed-lens eye. The old eye sees the sky as having a touch of cyan to it.

Link to comment

NewScientist readers are a persistent lot, here are Two more from the 19 April issue.

 

The first one is from one of the UK experts in holography.

 

1. I underwent a cataract operation involving eye lens replacements. Some time later I visited a research lab at the University of Cambridge. The team had just taken delivery of a UV laser emitting a beam with a wavelength of 355 nanometres, and was having trouble aligning it in their optical set up. I found I could see the beam clearly, and aligned it for them without difficulty.

When they asked me what colour I saw, I had to tell them that it was, disappointingly, no different from the violet light from their existing 405 nanometre laser, which they all could see.

 

2. There are widely reported inaccuracies about human colour vision. The absolute range of retinal sensitivity extends from near-ultraviolet to near-infrared. Strong, and possibly harmful, illumination is necessary to see these extremes. As we age there is increasing absorption of near-UV light by the eye’s lens, and so it becomes harder to perceive. A child can dimly see UV light with a wavelength down to 350 nanometres, but in older people this limit retreats to about 380 nanometres. Some people who have had an eye lens removed and replaced with a UV-transparent one can see down to about 310 nanometres. Below this, the cornea itself absorbs UV.

 

I wonder if the cornea of an insect eye also absorbs UV below 310 nm?

 

Dave

Link to comment

Please sign in to comment

You will be able to leave a comment after signing in



Sign In Now
×
×
  • Create New...