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Followup: Ultraviolet Vision After Cataract Surgery
xmas2003 writes "Several months ago, I posted to Slashdot about being able to see ultraviolet light after cataract surgery. While a lot of the discussion whimsically discussed the best way for 'Captain UV' or 'UltraMan' to use this 'super-power,' there were some people who were skeptical or (incorrectly) said this is Tetrachromatic vision. I've subsequently done more testing using an Oriel Instruments MS257 Monochromator and was able to see color down to 350nm — below the usual ~400nm limit of the visual spectrum. It's also easily demonstrable with a pair of 400nm and 365nm UV flashlights. Some readers who also have UV vision commented this can be quite annoying at black-lit Disney Rides, Halloween Haunted Houses, etc. Fortunately for me, it's just an interesting oddity so far. Along those lines, some interesting related stories about using UV vision during World War II and Star Gazing. Finally, many/most people end up getting vision debilitating cataracts, so my experience having a Crystalens implanted after cataract surgery may be informative."
Can you see through clothes?
If you can't read the line above. Then you don't have UV vision.
...when you have X-ray vision!
Seriously though, as someone who has a hearing range beyond the standard I sympathise with people forced to endure irritating stimuli that noone else notices and hence cares about. I remember having to leave a bar once because the tube was going on their old television; the high pitched screech was like nails down a blackboard. My girlfriend thought I was mad.
Seeing UV after cataract surgery proabbly isn't a 'tetrachromic' effect. Human eye lenses are naturally yellow at birth, browner as we get older, browner still and they start being called 'cataracts'. They filter out the UV at any age. So the retina never usually gets a chance to try out its UV-seeing ability using its basic trichromatic receptor kit.
-wb-
I read somewhere (on the net of a million lies) that Bees (and other insects) can see polarized light. Then you can see flowers in a whole way (and maybe better find your way home).
Or get circularly polarized contact lenses and see like a mantis shrimp!
What an awesome super power!
In other words, does your new ability simply "shift" frequencies ?
The relatively bright star Adhara (Epsilon Canis Majoris) is actually the brightest star in the sky in UV light. Of course you don't have pure UV vision but rather just a bit more UV bias.
However, since you seem to enjoy an experiment I suggest going somewhere where at least the brightest stars are visible, and comparing relative brightnesses between stars with a person with average vision.
Some background and a chart for Adhara below. It's close to Sirius which in turn is easy to find by using the belt of Orion.
http://stars.astro.illinois.edu/sow/adhara.html
http://www.rocketmime.com/astronomy/fig/CanisMajor_wAdhara.gif
This quite cool: http://en.wikipedia.org/wiki/Haidinger's_brush
I, the evil mutant Darklight, am the only one with power over the ultraviolet spectrum. If another emerged with such powers, it would threaten my Ultimate Ultraviolet plot for world domination. I must alert my co-conspirators Nucleon and Cheetahface and see if they can learn more about this "xmas2003". A curious choice for a superhero name... the "x" suggests some affiliation with the X-men and yet when I sucked out Xavier's brain he revealed nothing of this mutant to me. It also implies some sort of holiday theme, which is simply baffling. Perhaps he wears an elf costume?
Very well, xmas2003. I will play your game. We will find you, and then we shall see if your powers are real. If I find that you have been toying with me with false claims, then I will kill you quickly. And if I find that you have been telling the truth, then I will kill you... slowly.
After taking out those precious, precious eyes of yours, of course. AHAHAHAHAHAHAHAAAAH!!!!
-Darklight, Evil Mutant Overlord
I've also had cataracts surgery, when I was a toddler. And I've always noticed that UV has bothered me and not other people, but I've never thought about if I "see" UV, or at least see it in a way that others can't. Sometimes it's enough to cause my eyes to spasm. (In fact, my aversion is so strong, while reading this summary my mind _imagined_ seeing UV light, and my eyes spasmed for a few seconds in reaction.) Anyway, now I'm wondering if anyone else has this sort of reaction.
Lando lost Cloud City in a game of Sabaac to a Hutt who had marked the cards with ultraviolet pigment.
That was an amazingly detailed and quite interesting write up - I found the numerous close-up photos and descriptions quite informative. Based on your proclivity for detail I am very glad that you suffered from cataracts and not colorectal polyips.
When you have nothing left to burn you must set yourself on fire
A young adult scifi book I read long ago took advantage of the fact bees can see into the UV spectrum as a plot device to navigate through a forcefield that was invisible to humans, but was "bee purple". Here's a little more information on bees:
"Honey bees and people do not see eye to eye. Humans see the colors of the rainbow; red, orange, yellow, green, blue, indigo, violet (otherwise known as ROY-G-BIV). Although honey bees have a fairly broad color range, they do not see red and can only differentiate between six major categories of color, including yellow, blue-green, blue, violet, and ultraviolet. They also see a color known as "bee's purple," a mixture of yellow and ultraviolet. Differentiation is not equally good throughout the range and is best in the blue-green, violet and bee's purple colors."
Source: http://ag.arizona.edu/pubs/insects/ahb/inf6.html
Do the webs of writing spiders look like flowers now?'
Correct Horse Battery Staple: 72 bits of entropy. Enter "Correct H" into google. When it generates the phrase, that's
Cool, so Bee's don't need 3D glasses to watch Avatar?
Do white flowers look differently? I've heard that there are "other"
patterns that we (humans) can't see, but insects can due to their
ability to see more of the UV spectrum...
We're effectively talking about corrective adjustments made to the shape of the eye; should it be adjusted enough in such a way as a tighter bandwidth were better scattered in the eye, then it kinda follows that some of it may be picked up. The question is, do purples, indigos, and violets seem stronger to you then before?
Does this mean that for the affected patients, more UV is reaching their retinas than before? If so, how could that be a good thing? Seems like more damage would be on the way.
I'd have a personalized plate on my car, but "toxic bachelor" won't fit into 7 letters.
The retina of the eye is full of cells. These cells send signals to the brain. The brain is apparently somehow able to know which type of cell sends each signal, otherwise it wouldn't be able to distinguish between the R, G and B signals. How does this connection actually work? Since, when there are 4 types of cells, apparently the brain is able to use those 4 types just as well. So it doesn't seem the brain, in its just born state, is already designed to accept a certain amount of color types, it looks like it's somehow able to work with whatever input is available to it, where this input is a random messy combination of input signals from a whole retina full of cells of N different types...
Maybe the brain somehow figures out that certain cells send signals only in certain colored lighting conditions, and make something out of that? But I also thought that the retina already does some processing of the signals from the cells, so how is that one able to do it correctly even if someone has 4 types of cells? Is its processing color independent maybe?
A few years back my brother (who was about 14 at the time) got a Wii and was having trouble getting the controller to work. I was troubleshooting with him over the phone and asked him if the sensor bar was plugged in and he responded "I think so, no wait it's not. The light's not on." I asked him what light? The only lights on the Wii sensor bar are the infrared lights. He said he knew that, but they weren't on. Apparently he can barely see infrared light. I did some tests with some remote controls that do not light up when pressing the buttons and would ask him to tell me when I press the button. Not very scientific I know, but it was enough for me to prove that he does indeed see something. He can see the lights on remote controls, night security cameras, and of course the Wii sensor bar. They all appear very faint, but over Christmas I got him some cheap toy night vision goggles which apparently use infrared LED's and it was bright enough in a very dark room to act as a flashlight for him.
UV light and even blue light are damaging to the retina and UV light is a major contributor to cataract formation. The replacement lens you get after surgery may not block UV light at all (currently some replacement lenses do offer UV & blue light protection).
Cataract surgery patients are advised to avoid blue light therapy products and, obviously, direct sources of UV radiation. Of course, protecting your eyes from UV radiation is generally a good idea for everyone.
As someone who has a has a Grandfather with AMD (age-related macular degeneration) and I myself have, according to a genetic test, factors that make it more likely that I too will experience AMD, I try to protect my eyes as much as possible from both UV and blue light.
Stupider like a fox! - H.S.
How long it will take for procedures like this to become commonplace.
Perhaps not this EXACT thing, but basic upgrades to human capabilities through modern medicine. Currently, most upgrades are in place to correct deficiencies. From Lasik to prosthetic limbs, hearing aids to hair plugs... we limit ourselves to only restoring the "norm." Even most plastic surgeries are only trying to attain the looks we had in our youth. I guess a boob-job would count as an upgrade, but that's still in the realm of normal (for the most part) while something like UV bias is completely foreign to most humans.
I can't wait for all the slippery-slope discussions once people start going under the knife for routine upgrades. "I've got a doctors appointment this afternoon to get my spinal reinforcements tightened and my xray vision re calibrated to focus on double-X chromosome subjects."
That's weird, you mean not everyone sees that? When I put on my polarized shades in the car my window tinting has those little spots all over it (at least, as far as I can see). I just assumed that's the way it was for everyone.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black
My father is in his mid 70s and had cataract surgery.
Before the surgery, for years, he hardly read anything and he was the most tech phobic of computer phobes, never saying why.
After the surgery he started reading books, I convinced him to get an iMac ( instead of Vista, this was a few years ago )and to take the Apple store's classes.
Years later he has his own web sites and sends me email.
You can keep your UV vision, I have a minor miracle of my own.
At least the Wood anemones do http://www.naturfotograf.com/UV_ANEM_RAN.html
So our hero could go to a botanical garden or contact a botanist to see if there is some unexpected patterns to find and perhaps which flowers to look at.
As somebody who is colour blind and undergone some extensive testing for it, I've been told by several people that the "normal" range of human vision between 400nm to 700nm is more or less an average. Everyone is different, and just as some people can naturally run a mile in 6-7 minutes with little training while others would have trouble walking a mile in 20 minutes, it is the same with our vision. IMO, a more true statement would be that the "weighted average" of human vision is 400 to 700nm, but the extreme ranges *might* go anywhere from say 350, 360nm to perhaps 720 or 730 nm.
For example, even without a yellowed cornea, some people may not see into the UV at all. There are also suggestions - would not go so far as to say a sound theory - that some well known artists from days past had, perhaps without ever knowing it, natural extended vision into either the UV or IR, or perhaps even both. Just as it is claimed that some famous musicians from the past had a naturally extended range of hearing.
Another thing to be aware of is that, at least IMO, the medical profession as a whole really seems to have little interest in this area. Specific example, I am colour blind, but it is very poorly understood. Also, since childhood, I have been extremely sensitive to bright light, but my night vision is superb, and apparently above that of the average person. I cannot tell you how many specialists I have either called or visited over the years, but the response is generally "I don't know" or "well, just live it it". It almost seems to me that if you cannot treat it or fix it right away, and you aren't going to die from it, why bother with it. so I have a small fortune invested in prescription eyeglasses, and I wear them even on cloudy days. You get some weird looks, but you get used to it.
As for "proof", I can understand dealing with skeptical people. In terms of my own night vision, I had trouble even convincing my wife when we were first married. I solved that one real quick one night camping. Walking from our campsite to the washrooms, I left the flashlight behind. I was able to find my way no problem, but my wife keep tripping over rocks or branches in the dark. Even holding her hand she keep tripping or bumping into things. She sure wasn't impressed, but she has never doubted me since. :)
Most cephalopods see the polarization of light as well, but they are colorblind so that's not much fun.
horror vacui
ok that is new to me - i always assumed (like you) that that was normal for polarized glasses.. although it does make since on why LCD's always looked odd and unevenly lit to me.
'...if only "Jumping to a Conclusion" was an event in the Olympics.'
Umm, are you saying that UV lights are not supposed to be bright purple..?
I avoid looking at them in clubs, raves, etc. because they're shine too bright and I know UV is harmful.
I dunno what to think now. Never had an eye surgery... I need to test this thing.
When my oldest was a baby, she reacted strongly to infrared light. My husband tried to get some video of her sleeping in a very dark room, dark hall behind him, no light anywhere. The infrared from the camera woke her up, and she covered her eyes and cried. She was only a few months old at the time, but it was very clear that the infrared was bothering her quite a bit. I have no idea if she can still do that, have to test it sometime.
What 'color' does the light appear to be? Does it appear to be red/reddish? Monochromators pass higher order diffraction. When set to 350nm, 700nm light passes through as well. Also, you should stop shining UV light into your eyes. It is very damaging.
My vision is augmented.
But I did get X-ray vision... it's not as good as you'd think. For one thing, I'm never going in to the senior center ever again!!!
No one ever had to evacuate a city because the solar panels broke!
I remember a security camera at wendys which would show some peoples black jackets as being purple and other black objects such as computers as black. It must have been more sensitive to the UV spectrum than a normal camera.
It sounds potentially dangerous, depending on the intensity that leaks through. Consider that the retina is a part of the brain, what you're doing is exposing your brain to UV light, and while not directly ionizing it's enough to disrupt or initiate chemical reactions that doesn't belong there.
So aren't people supposed to see black lights? I see them extremely well and they obfuscate everything else around. I'm literally lost in any place with too many of such lights, especially when they start bouncing off the walls and the floor, but most people seem to navigate those places without any problems. I have a congenital open angle glaucoma, one of my eyes is totally blind, and the other retains only 10% of sight, but can see color very well, possibly better than usual, as I've had lots of arguments about colors with people where I turned out to be right (such as the backlight (seen through the table in the lid) and keyboard LEDs having a very noticeable pink hue on the MacBook Pros, while lots of people kept telling me that they were white).
Don't think I'd opt for UV eyesight. Wouldn't that make all the stains on those hotel mattresses quite apparent? I'm OCD enough as it is. I'd be clinical if I could see how dirty the world really is.
The spots you see on your window tinting is probably due to polarization variations in the film. My sunroof has them. Haidinger's brush is more subtle. Pull up a blank white page on an LCD monitor, stare at the centre and slowly tilt your head. If at one point you see the blue/yellow bow tie pictured in the article then you're seeing Haidinger's brush.
I imagine that animals that can see UV perceive the UV colour as distinct from the other colours. And I suppose that is a function of the brain. Those people that can see UV -- what colour do they perceive, actually?
I see the spot/crosshatch pattern on car windows when I wear polarized shades. I don't see Haldinger's brush, though, when I'm wearing no glasses. The pattern on car windows comes from the glass-tempering process.
Program Intellivision!
At the shopping mall nearest my home town, there is a department store that has had one of those ultrasonic bug & pest repellers installed above the doors since the mid 80s. As a kid, I couldn't stand being within 50 feet of those doors for any length of time; it wasn't just annoying, it bloody well hurt! While my father and I waited thereabouts for my mother to meet us, I thought I'd crawl out of my skin, and neither of them ever believed me about it.
Now in my early 30s, I recently went back, having forgotten about the damn thing. I walked through those doors and instantly felt uneasy, along with a pressure in my head and sudden ringing in my ears. It went away quickly, but came back as I later approached the doors to leave; then I remembered the device which, sure enough, was still above the door. It isn't the piercing sound that stabbed my ears as a child -- I assume my hearing has declined somewhat already as I've aged -- but man, it still makes my head throb. And nobody else seems to notice it.
A preposition is a terrible thing to end a sentence with.
Enquiring minds want to know.
I don't think that's the Haidinger's brush effect -- I believe what you are seeing in the car window is the variability in birefringence from the strain pattern caused by the process of toughening the glass.. From the article:
The strain pattern resulting from tempering can be observed with polarized light or by using a pair of polarizing sun glasses.
Humans have some limited polarization detection. Besides the already-linked Haidinger's Brush, you can also pick out polarization against the sky, if the sun isn't directly overhead and you know what you're looking for. It's very subtle, but it's there.
The Quirkz Handbook of Self-Improvement for People Who Are Already Pretty Okay
They whine at 15750Hz, which is the line rate of NTSC. That's high frequency, but well within the "20kHz" human norm. Older people often can't hear it, since high frequency hearing drops off with age, but many people can.
without UV vision were able to beat out the humans with UV vision. Darwin has his quirks.
now we need to go OSS in diesel cars
I'm sure that many here have deuteronamoly http://en.wikipedia.org/wiki/Deuteranomaly#Anomalous_trichromacy (often ignorantly referred to as red-green color blindness) or other color vision deficiencies. What many don't realize, even some of those who have it, is that we are better at detecting people or objects that have been camouflaged due to a better ability to spot shapes, shades and movement. Is it better? Mostly not, from my personal experience. But it can come in handy in some very special situations.
This UV problem is mostly related to older generation IOLs (intraocular lenses). For citation, consider this article from 2005
There is ample evidence that suggests that blocking UV is good, and, because we are not aware of any downside to using a UV-absorber, cataract surgeons for the most part have adopted this technology; virtually 100% of IOLs now contain UV-absorbers.
Last month, my wife (who is also an optometrist) had IOL replacement in both eyes. The opthamologist noted that there were no options worth considering that didn't have UV protection.
Of course different lenses offer differing amounts of UV protection, though, so chosing wisely is still a requirement (as always).
this is just a test comment. please ignore.
Remember the "night vision" camcorders that Sony introduced 10 or so years ago? These camcorders have the ability to switch the IR-blocking filter out of the optical path so the camcorder can pick up near-IR wavelengths, and can record images illuminated by IR LEDs. There was some wailing and gnashing of teeth upon their introduction as they could record a semi-X-ray vision effect; you could sort-of see peoples' knickers through some clothes.
So I would think you would need vision at the other end of the spectrum to realize the full glory of X-ray vision.
I downloaded an app the other day on my iPad called "Color Uncovered" for exploratorium.edu (I thought it would be cool to go over with my kids - and it was). One of the items in the app was a mention that, like a honeybee, impressionist painter Claude Monet could see ultraviolet light following cataract surgery.
The below quotes are from the app (I just happened to have my iPad handy as I read this and remembered basically where it was).
"Actually your eyes are partially equipped to see ultraviolet light. The color-sensitive cone cells in your retina can detect it just fine. But the lenses of your eyes filter out the ultraviolet light before it can reach your retina, so you never get a chance to see it."
"Late in his career, Monet developed a cataract that dulled his vision. In 1923 he underwent cataract surgery to remove the clouded lens. Without a lens in the way Monet was suddenly able to see ultravioet, which looks whitish blue to humans. The change is apparent in his painting as he began to pain his water lilies - which look white to the rest of us - a pale blue."
My present is the activity I am currently engaged in with the purpose of turning the future into a better past.
You are anot unique. I have had cataract surgery on both eyes many years ago and have also noticed a different frequency response in either eye while looking at uv bug lamps. In the left eye the lamps appear much brighter than the right. I have the serial numbers and manufacturer infomation and could research it further, but I did not think I could actually see into the uv spectrum and though it was likely a difference in the manufacturing process with the addition of a uv filter since the lenses and surgeries were several years appart.
UV can be used to visualize blood, DNA, etc... see where murders and creampies were performed...
Yeah, flowers have interesting UV patterns.
Will you be starring as the next movie of the Riddick series (Pitch Black, etc)
I am able to see a little bit into the UV spectrum, and I'm able to hear exceptionally high pitched sounds. I find it annoying, because the stuff most people don't notice, they don't bother to fix, so whenever I see a truck on the highway with a UV (blacklight) illuminator on it for decoration, it gives me a headache. God forbid anyone should watch a CRT tv or computer monitor. I definitely hear solidstate computer components making noise even though they have no moving parts. Usually it's a sign of imminent failure, and I use this to help diagnose flaky or failing computers sometimes.
What use is there for it? Not much. But you can see if people have washed their clothes recently, because the laundry detergent residue makes them glow a little bit. And I suppose if you spray some place with luminol you should be able to see blood, without carrying a blacklight. No big deal, because if you're carrying luminol, you're probably carrying a blacklight. So like I said, there's not much use...
Some LED displays emit into the UV spectrum. These hurt my eyes, and I have to look away. I suppose that's useful - less likely to develop cataracts at a later age, I suppose. Same goes for blue LED christmas lights.
But finally - My vision in the infrared is dimished a little bit. You (the writer) might want to see if your Red vision extends as far down as other peoples' red vision. I first noticed this deficiency in myself, when I was around 17, a bunch of us went bowling, and the score was kept on a TV screen. Numbers were written in white, spares written in blue, and strikes written in red. I asked someone why there was nothing showing in any of the frames where we had strikes, and she acted a little weird, joked it off. But later I asked again, and she realized I was serious. "You mean you can't see that?" It was just a deep deep color of red. Just barely outside my visible range, but still within everyone else's visible range.
On rare occasions, I discover I can't see red. But usually I can. I guess my frequency response is just slightly skewed from "normal." Biased away from the infrared, and toward the UV. It could be caused by pigmentation, or lack thereof. I am exceptionally white. I am not albino, but throughout my life, I have frequently been mistaken for one. I am the whitest (and pinkest) non-albino you've ever seen in your life.
> I could hear radio towers when we drove by them.
You do know that radio waves are electromagnetic, and your ears work on pressure waves in the air, right?
Are you sure your radio just isn't broken?
Zone-tempered glass? I always wear polarised sunglasses, and have seen this on only some cars. (Thankfully mine isn't one of them.)
I've found that a cataract is easily visible with a UV LED flashlight because the cataract fluoresces bright green. I do not recommend looking at the light very long however, because the UV will accelerate the protein cross-linking and worsen the cataract. And the glow will freak out some people; it looks unearthly.
I got my cataracts, by the way, from working 12 to 16 hour deathmarches and staring at screens then going home and collapsing into bed without removing my extended-wear contact lenses. Too long a period of this abuse (at a start-up) cut oxygen to my corneas, this then affected the electrolyte balance in the lens cells, and triggered damage to the colloids that constitute the contents of these cells. This caused the crystalin protein molecules to begin cross-linking to form cataracts. Normally, these molecules are held apart by delicate electrostatic forces, but various factors will disrupt those and begin the spiral into dysfunction.
I urge people who wear contact lenses and work long hours for weeks on end to make sure they do not sleep in their lenses, and that they take proper eye nutrition supplements. The problem is easy to avoid, and hell to pay once it happens.
This is certainly public infromation. There are many jurisdictions in the world that prohibit common individuals from possessing night vision equipment. Now that his BODY has become such equipment, can he be prohibited from traveling to certain places around the world?
Let us take it further and don our "government" hats. This individual can do things that perhaps the rest of the species cannot do, namely see a range of light that humans normally cannot see. As a government official, one will invariably exploit what I call "Political Augustinianism". This means that since all men are fallen in the theological definition, the political translation of that idea becomes "every individual a criminal" therefore making "everything a weapon" a.k.a "everyone has something to hide". This will eventually lead to a "fix" that filters out wavelengths that governments do not want the loyalty-unsworn to see. Therefore this man may be coerced to have that lens replaced by one that the government approves.
IMHO, the retina may not be designed to be exposed to those wavelengths and so "Nature" would not approve of it either.
==//==
The spots you see on your window tinting is probably due to polarization variations in the film. My sunroof has them.
The spots are differences in stress in the glass due to tempering. Glass under stress polarizes light differently than glass at rest - I used to help out in at a scientific glassblower's and we had a tool that used polarizing filters to see if glass had residual stress after we worked on it.
I've heard that the spots are glass under stress. The spots on my sunroof are very prominent, but my windshield and side windows don't show spots that are nearly as obvious (they're also not tinted). Is that because the factory is more careful with windshields and side windows? The OP also specifically mentioned tinted windows, by which I assumed he meant side windows with tinting applied.
What was the glass going to be used for that you wanted to check for residual stress?
I would try staring at the sun. For long periods of time. That MIGHT help you rid yourself of that annoying affliction.
w/ original equipments cataracts, my visual response has been slowly slipping towards the UV spectra over many (30+) years. I know this quantitatively through lifelong professional measurements of optical materials and optical spectrum. Early red lasers (longer wavelength than current laser pointers) that I made were invisible to me, yet strong to other observers by eye. I still rarely see 'red' laser pointers unless the intensity is very bright compared to ambient light. Desktop publishing of red on black looks like black on black depending on the choice of red wavelength (my school colors are red on black). Note that people (including me) can actually see all the way out to IR wavelengths if the intesities are strong enough - wavelength response depends not just on wavelength, but intensity as well. A single 808nm laser is typically not visible, while a fiber coupled array of 808nm lasers can be easily seen. I've done enough work with near-UV lasers and materials to know the difference between UV-induced fluorescence (violet colors from 'blacklights' and other phosphorescent materials) to be able to see 365nm emission from gallium nitride that has a 'clean-enough' emission spectra to have no visible light emission (as measured by spectrometers). The aspect of this wavelength sensitivity variation over time that does not make sense is the UV shift over time. As the OP demonstrates, 'new' (non-UV-degraded) lens have less degradation to UV response than 'old' organic lenses that are naturally UV- and vis- clouded over time. Perhaps this will all come down to a resonant effect related to some characteristic dimension, such as the recent studies of Morpho butterfly wing dimensions. Some aspect of human vision seems to develop with properties inverse to temporal physical properties of common materials. This relation require further study.
I vaguely remember a fictional story I read ~20 years ago about someone who had had recent cataract surgery and was kidnaped by smugglers, forced to be their spotter watching for a signal from a UV flashlight on a boat offshore running dark. The story made a point about how people with cataract surgery but no implanted replacement lenses were able to sense UV light (not necessarily "see", but sense).
In theory, practice and theory are the same. In practice, they rarely are.
I had a lens removed from one of my eyes when I was a child and wear a hard contact lens as a replacement. I noticed very early on that I see more UV in that eye than the normal one. UV lamps, those insect killer things, etc, all show as a more flourescent purple in the damaged eye.
The spots on my sunroof are very prominent, but my windshield and side windows don't show spots that are nearly as obvious (they're also not tinted). Is that because the factory is more careful with windshields and side windows?
The sunroof is horizontal. Gravity causes shear stresses in the glass. Windows are relatively vertical and gravity causes mostly compressive stresses in them. Most materials endure compression much better than shear.
Try pushing upward in the middle of it and see if the spots change.
What was the glass going to be used for that you wanted to check for residual stress?
I'm not GP, but IIRC a lot of electronic tubes and bulbs are made from hand-blown glass globes.
You could potentially help Rowdy Roddy Piper stop the alien invasion!
"Powers. I have them."
How long before makers of replacement lenses start touting UV vision in their ads?
I had an AOL (artificial optic lens?) implanted around 1996 due to a cataract from eye injury. Black lights at places used to give me a headache due to...i'm not sure, i thought it was the disparity between what my two different eyes were seeing (they glow a bright purple to the damaged eye). It's been so long that it no longer causes headaches, but it's still...odd.
When I asked my opthamologist about it he said something about "a UV filter" in the lens.
He also wanted to replace the lens with a newer & better one only a few years after the surgery...but I'm squeamish about it, understandably (having stitches cut out of your eye with a scalpel is a bit disconcerting).
So I forwarded this page to an ophthalmologist and apparently it is a well-known phenomenon for new IOL's.