# Glowing (eye) pupils in black light **URL:** \ **Category:** Factual Questions\ **Created:** [January 27, 2005, 10:31am UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899 "2005-01-27T10:31:36Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![robotic\_panda](https://avatars.discourse-cdn.com/v4/letter/r/ed8c4c/32.png) [@robotic\_panda](https://boards.straightdope.com/u/robotic_panda)\ **Post date:** [January 27, 2005, 10:31am UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/1 "2005-01-27T10:31:36Z")
I have been wondering this for quite a while. When my eyes are exposed to a black light, a common, flourescent tube type, my pupils glow greenish blue. When my friends and I discovered this, we tried in every way to recreate it, with all of them, but I was the only one with the Glowing Pupils. The only way we ever duplicated the effect was with my friend’s cat, and her eyes glowed exactly the same. We never had another cat to try it with, and I still wonder to this day, why? Why do my pupils glow in flourescent black light, and no one else’s? If you can try this on yourself, or a cat, report back… I just want to know why. ---
**Author:** ![x-ray\_vision](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/x-ray_vision/32/351_2.png) [@x-ray\_vision](https://boards.straightdope.com/u/x-ray_vision)\ **Post date:** [January 27, 2005, 1:30pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/2 "2005-01-27T13:30:06Z")
From [here](http://potosisd.k12.wi.us/staff/hoier/Question%20Box.htm#Animal%20eyes) > [@](#): > > "There is a layer at the back of the retina termed the tapetum lucidum which acts to improve low-light vision by reflecting light. The chemical composition of this layer, in particular that of lipid vesicles within the cells, affects its light modifying properties. There are species-specific differences in this layer and in the retina generally - including the degree of vascularization i.e. the concentration of red blood cells within the tissue. These factors influence the color seen by you, the observer of reflected light. In other words, different animals have different sorts of pigment in their tapetum, and different pigments reflect a different color of light. " It seems you are a different species than your friends. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 27, 2005, 2:15pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/3 "2005-01-27T14:15:46Z")
Not wanting to be the harbinger of doom, but is there a history of cataracts in your family? ---
**Author:** ![picunurse](https://avatars.discourse-cdn.com/v4/letter/p/7bcc69/32.png) [@picunurse](https://boards.straightdope.com/u/picunurse)\ **Post date:** [January 27, 2005, 3:25pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/4 "2005-01-27T15:25:05Z")
I’m not sure how accurate the information in **x-ray vision** ’s link is, but different breeds of cats reflect different retinal colors. Siamese reflect red, Persion reflect green. My experience with human retinal color is very limited (read: I fainted in nursing school watchine eye surgery.) I do know that cataracts are lens related, the color one sees reflected in low light is from the retina. If cataracts are present there would be no reflection. Cataracts cause blindness by preventing light from entering the eye, so obviously, none would reflect back. ---
**Author:** ![user\_hostile](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/user_hostile/32/474_2.png) [@user\_hostile](https://boards.straightdope.com/u/user_hostile)\ **Post date:** [January 27, 2005, 4:00pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/5 "2005-01-27T16:00:53Z")
Do you or your cat wear contact lens? ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [January 27, 2005, 4:05pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/6 "2005-01-27T16:05:58Z")
The **Robotic Panda** has glowing eyes? Does this strike anyone else as _not strange_ ? 😃 ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 27, 2005, 4:30pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/7 "2005-01-27T16:30:18Z")
> [@picunurse](#): > > I’m not sure how accurate the information in **x-ray vision** ’s link is, but different breeds of cats reflect different retinal colors. Siamese reflect red, Persion reflect green. My experience with human retinal color is very limited (read: I fainted in nursing school watchine eye surgery.) I do know that cataracts are lens related, the color one sees reflected in low light is from the retina. If cataracts are present there would be no reflection. Cataracts cause blindness by preventing light from entering the eye, so obviously, none would reflect back. Cataracts cause a cloudiness of the lens; my reasoning is that the cloudy material could itself be fluorescing and it could be this that appears as a glow through the pupil in this particular case. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [January 27, 2005, 4:48pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/8 "2005-01-27T16:48:54Z")
> [@](#): > > The fluorescence of the human lens is caused by accumulation of advanced glycation end products formed by non-enzymatic glycation on lens proteins. Advanced glycation end products are important for the pathogenesis of diabetic long-term complications. Lens fluorescence may thus serve as a biomarker of the extent of tissue-damage related to advanced glycation end products which may be of importance for the management of diabetic patients. [here](http://www.danmedbul.dk/DMB_2004/0304/0304-phd/DMB3651.htm) ---
**Author:** ![vetbridge](https://avatars.discourse-cdn.com/v4/letter/v/b5e925/32.png) [@vetbridge](https://boards.straightdope.com/u/vetbridge)\ **Post date:** [January 27, 2005, 5:17pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/9 "2005-01-27T17:17:37Z")
> [@Mangetout](#): > > Not wanting to be the harbinger of doom, but is there a history of cataracts in your family? Good point, **Mangetout**. I do not know specifically about human lenses, but in dogs and cats the lens will flouresce under UV illumination. ---
**Author:** ![Colophon](https://avatars.discourse-cdn.com/v4/letter/c/f05b48/32.png) [@Colophon](https://boards.straightdope.com/u/Colophon)\ **Post date:** [January 27, 2005, 6:11pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/10 "2005-01-27T18:11:52Z")
So, **panda** , are you diabetic? **Squink** ’s link suggests there may be a, uh, link. ---
**Author:** ![down\_by\_law](https://avatars.discourse-cdn.com/v4/letter/d/65b543/32.png) [@down\_by\_law](https://boards.straightdope.com/u/down_by_law)\ **Post date:** [January 27, 2005, 6:31pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/11 "2005-01-27T18:31:58Z")
my dad had cataracts and had new lenses (i think) put into his eyes. he looks like the dog now when light hits his eyes. creepy. ---
**Author:** ![CynicalGabe](https://avatars.discourse-cdn.com/v4/letter/c/3e96dc/32.png) [@CynicalGabe](https://boards.straightdope.com/u/CynicalGabe)\ **Post date:** [January 27, 2005, 6:48pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/12 "2005-01-27T18:48:55Z")
I, for one, welcome our new Robitic Panda overlords. ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [January 27, 2005, 7:19pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/13 "2005-01-27T19:19:59Z")
> [@picunurse](#): > > Siamese reflect red It’s scary as hell too. You wake up in the middle of the night. A cool breeze wafts through the room. A beam of moonlight, and then… Demon Cat! ---
**Author:** ![robotic\_panda](https://avatars.discourse-cdn.com/v4/letter/r/ed8c4c/32.png) [@robotic\_panda](https://boards.straightdope.com/u/robotic_panda)\ **Post date:** [January 27, 2005, 11:05pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/14 "2005-01-27T23:05:03Z")
Hmmm… well I really don’t think its cataracts, i’m only 22. I’m also not diabetic, and I really didn’t think it was the lens, as it only occurs in the pupil area, making me think it is inside my eye. I’m not aware of cataracts occuring in the family. Also, no, no contact lenses, no eye operations ever, nothin. Just GLOWING PUPILS! But only under\* black light\*. These responses have been… interesting. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 27, 2005, 11:06pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/15 "2005-01-27T23:06:10Z")
Is your vision affected at all by this phenomenon when it occurs? ---
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [January 27, 2005, 11:13pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/16 "2005-01-27T23:13:21Z")
> [@robotic\_panda](#): > > I really didn’t think it was the lens, as it only occurs in the pupil area, making me think it is inside my eye. [The lens](http://www.zeiss.de/de/ophtalmic/comp/home_e.nsf/0/3153762a13673c74c1256918004b63e4?OpenDocument) is inside the eye, behind the pupil. ---
**Author:** ![robotic\_panda](https://avatars.discourse-cdn.com/v4/letter/r/ed8c4c/32.png) [@robotic\_panda](https://boards.straightdope.com/u/robotic_panda)\ **Post date:** [January 27, 2005, 11:13pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/17 "2005-01-27T23:13:43Z")
> [@Mangetout](#): > > Is your vision affected at all by this phenomenon when it occurs? Not at all… It was pointed out to me while a bunch of us were sitting around in just black light. It looks really cool, I can see just fine, and I have no idea why it happens to me and no one else. I’ve searched for this over the years on Straight Dope, no one ever asked… I’m beginning to wonder if I AM a different species. Much would be explained. ---
**Author:** ![robotic\_panda](https://avatars.discourse-cdn.com/v4/letter/r/ed8c4c/32.png) [@robotic\_panda](https://boards.straightdope.com/u/robotic_panda)\ **Post date:** [January 27, 2005, 11:15pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/18 "2005-01-27T23:15:42Z")
> [@Fear Itself](#): > > [The lens](http://www.zeiss.de/de/ophtalmic/comp/home_e.nsf/0/3153762a13673c74c1256918004b63e4?OpenDocument) is inside the eye, behind the pupil. :smack: Duh. But yeah… I don’t have diabetes or cataracts. But now I get to worry. Thanks, guys! 😃 ---
**Author:** ![Bosda\_Di\_Chi\_of\_Tricor](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bosda_di_chi_of_tricor/32/16845_2.png) [@Bosda\_Di\_Chi\_of\_Tricor](https://boards.straightdope.com/u/Bosda_Di_Chi_of_Tricor)\ **Post date:** [January 27, 2005, 11:54pm UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/19 "2005-01-27T23:54:26Z")
Does the red glow enable you to fire lasers from your eyeballs? Have you really, really _tried_ to fire lasers from your eyeballs? ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [January 28, 2005, 12:27am UTC](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899/20 "2005-01-28T00:27:35Z")
It might just be one of those things - everybody is a bit different, but I’d think it more likely that it means you have something happening in your eyes that isn’t quite normal (that’s not to say it has to be abnormal in a really bad way). Of course it might not be cataracts or diabetes… It could be kidney or liver failure… OK, probably not - but what I’d do, if I were you, is to see the doc and tell him about this conversation; maybe ask if he’ll do a blood test. Don’t worry though, because worrying is bad for you. [Next page](https://boards.straightdope.com/t/glowing-eye-pupils-in-black-light/286899.md?page=2)