Talk:Pupil

Goat

Notice that the tag on the goat reads 666. -- Does it have 6/6/6 vision? I'm sorry for all you feet users but this joke uses the metric system. ( And 20/20/20 just isn't funny.)::: Coming to think about it, It was probably added with a computer software.

i see no goat...75.5.73.175 (talk)

Constriction of the pupils in certain situ. In need of more references

A little bit less important then Hell's evil goat, The last part of the article states that the pupil are affected by some situations(Flight or flight). Does anyone have a reference to that statement?

Miosis = ConstrictionGMoMD (talk) 08:48, 28 May 2008 (UTC). Sphincter Pupillae constricts pupil during accommodation and when there is bright light, this happens due to parasympathetic nerve activity.

Mydriasis = Dilation. Dilator pupillae, dilates pupil when there is low-intensity light and when a person is excited or is in a state of fear. Sympathetic nerve activity makes this happen.

Dilation of the pupils in certain situations.

Does anyone know about dilation of the pupils when a person is in a situation in which they are frightened or in a situation of extreme fear? Thanks. -- Xer0X 12:44, 22 December 2005 (UTC)

You may want to see Flight or fight response, though it doesn't seem to have anything on the pupil specifically.

Oh, thanks for the link, the page is very interesting. But if anyone has an answer as to the effect of stressful situations (fear, fighting, etc...) on the pupils please take a quick minute to respond. --Xer0X 12:57, 22 December 2005 (UTC)

Your pupils dilate when you are frightened. From the article: "Dilation occurs when signals from sympathetic fibers cause the iris dilator muscles to contract". Sympathetic fibers are stimulated in stressful conditions. Strangely, I came here to know if the Hellsing OVA was wrong in having a surprised character's pupils contract.—The preceding unsigned comment was added by 70.81.44.238 (talk • contribs) 03:10, 19 April 2006 (UTC).

When the red-eye effect isn't red

According to the article, "When an eye is photographed with a flash, the iris cannot close the pupil fast enough and the blood-rich retina is illuminated, resulting in the red-eye effect." Yet when the photograph is of a cat, the effect is sort of a bluish-green, not red at all, even though cats' blood is as red as anyone else's. Why? Angr (talk • contribs) 15:21, 6 April 2006 (UTC)

I believe that this is because of a reflection off of the cat's eyes, but I could be wrong. --Xer0X 18:35, 6 April 2006 (UTC)

I've heard that it's because there is a reflective layer in the cornea of cat (and other nocturnal animal's) eyes. The idea was that it reflects light that passes through the cornea back through the cornea, improving night vision. --216.84.45.198 19:48, 30 May 2007 (UTC)

See retroreflector and tapetum lucidum for the answer. 160.36.58.205 16:20, 28 June 2007 (UTC)

Other Cause of Dilation in Human

If you look at the reflection of your right eye in the mirror, and close your left eye, you will see your right pupil grow. This is probably why the world doesn't seem dimmer when you close one eye.—The preceding unsigned comment was added by Svendsgaard (talk • contribs) 22:17, 20 April 2006 (UTC).

Alcohol contradiction

The section about dilation says: "Certain drugs cause constriction of the pupils, such as heroin. Other drugs, such as alcohol, cause pupil dilation. Another term for the constriction of the pupil is miosis. Substances that cause miosis are described as miotic."

But the article for miosis has alcohol listed as constricting drug instead of dilating.

Well, this confused me, so I had a look, and couldn't find an obvious answer as to what alcohol does to pupils:

• Crash Course Psychiatry, Cameron A, 2nd Ed, 2004. Mosby, ISBN 0-7234-3340-2 says that central nervous system depressant abuse causes miosis. (Alcohol is a central nervous system depressant - Rang, Dale, Ritter, Moore, Pharmacology 5th E, Churchil Livingstone, ISBN - 0-443-07145-4)
• Brown B, Adams AJ, Haegerstrom-Portnoy G, Jones RT, Flom MC. Pupil size after use of marijuana and alcohol, Am J Ophthalmol. 1977 Mar;83(3):350-4., PMID-322494 says that alcohol has no effect on pupil size

Can anyone else clear up the picture? Ged3000 (talk) 16:27, 16 May 2008 (UTC)

dilation

does any one know if your pupils dialte when you tell a lie —Preceding unsigned comment added by 24.12.178.76 (talk) 00:29, 13 November 2007 (UTC)

Probably, because lying is associated with sympathetic stimulation, i.e. fight or flight response... sweating, rapid heart rate etc. This is just my assumption. cyclosarin (talk) 03:33, 26 January 2008 (UTC)

Dilation/Constriction

Does anyone have an idea (wich then could be added to the article) what causes eyes to periodically constrict and dilate in standard light? They have a cycle (Dilation - Constriction - Dilation) of about four to six seconds. 89.190.0.228 (talk) 09:09, 13 December 2007 (UTC)

It is called Hippus. there is a page on it. —Preceding unsigned comment added by 24.21.28.240 (talk) 22:32, 13 February 2009 (UTC)

Vandalism

Someone vandalised the picture of the goat head by changing the ear tag # to 666. 97.86.45.216 (talk) 07:40, 15 October 2008 (UTC)

Different pupil sizes

If a persone's pupils are two different sizes, (e.g. my right pupil is bigger than my left), does it indicate an improper developement or deficiency of the brain, or is it a common phenomenon in people?--41.182.54.9 (talk) 15:56, 5 April 2009 (UTC)Eugene

Dilating pupils on command

My friend has control over his pupils. He can simply change the size on command. How is this possible? —Preceding unsigned comment added by 87.59.254.28 (talk) 18:00, 31 August 2009 (UTC)

light and dark

whin the pupil is in light it is small this attrachson happins whin the puoil has to much light in its way of site so it go small to see in the darck it will go whider so moer light is let in not like the light part is it. —Preceding unsigned comment added by 216.249.72.203 (talk) 17:43, 7 January 2010 (UTC)

Overly anthropocentric

The eye article is more balanced and covers the subject matter much more objectively. Could someone dig up more information about different types of pupils? I've understood that some penguins even have shape-changing pupils - one shape for air and one for water. --Khokkanen (talk) 23:53, 29 May 2010 (UTC)

Effect on resolution

Does the diameter of pupil affect the resolution eye can see? —Preceding unsigned comment added by 91.99.164.128 (talk) 13:54, 19 June 2010 (UTC)

It should affect resolution in the same way it does for cameras: Too big and aberrations cause problems (e.g., older people at night); too small and you would run up against the diffraction limit (although I don't know if that's actually an issue).

I believe I've read that the human pupil diameter results in a diffraction limit that closely matches the size of rods and cones. —Ben FrantzDale (talk) 13:11, 13 October 2011 (UTC)

Pupil shape

Animal pupils are sometimes vertical - it would appear that this is the same as a number of small pulis stacked on top of each other. This would give more light and the same sensitivity to movements/prey moving horizontally.

If there is a predator that has a horizontal pupil than one could expect it's prey to move vertically. — Preceding unsigned comment added by 122.108.195.232 (talk) 06:50, 13 October 2011 (UTC)

I have just added a section on pupil shape. During my research for the section I found that cuttlefish and octopus have horizontal pupils and of course their prey can move vertically.__DrChrissy (talk) 17:46, 3 December 2012 (UTC)

Are all birds' pupils circular

In researching the section on pupils of Non-human animals, I have realised I have not seen any references to birds having non-circular pupils. I have seen one reference that penguin pupils become slits when they enter the water, but I don't thing the source is trustworthy. Does anyone know if all birds' pupils are circular? __DrChrissy (talk) 18:30, 5 December 2012 (UTC)

A cat with vertical slit pupils

It needs a different picture. A REAL picture, not a flagrantly modified one. This isn't deviantart, it isn't a place to showcase your photoshop skills, it's frigging wikipedia. I'm not going to go to the effort because I know from experience that any change I make always is undone in like 5 minutes by someone else who thinks he knows better, even though he's wrong, I don't feel the need to rearrange the deckchairs on the titanic. But if one of you self-assured arrogant busybodies actually has eyes and looks at the picture of that cat and thinks about what you're seeing for 5 seconds, you can see what I'm saying is obviously correct.

75.175.48.64 (talk) 14:15, 23 August 2014 (UTC)

Blackness of the pupil

I think it is a persistent widespread misconception that the blackness of the pupil results from the "light rays entering the pupil are either absorbed by the tissues inside the eye directly, or absorbed after diffuse reflections within the eye that mostly miss exiting the narrow pupil". Although the retina is not very reflective, instead the most important reason for the blackness is "that the eye and the head of the observer block the ray of lights that illuminate the part of the retina he or she is trying to observe" . This effect is caused by the way the cornea and the lens work to uniquely map any point from the outside world onto a unique point on the retina. In other words, to see the retina of an other person you would have to shine a light from your own eyes, which in normal circumstances is impossible without blocking your line of sight.

However, doctors can look into a person's eye and view the retina by using an Ophthalmoscope. Indeed this instrument works by placing a light source close to the eye of the observer without blocking the line of sight from the eye of the observer to the retina of the other person.

I think the article can be best updated by using the quote "that the eye and the head of the observer block the ray of lights that illuminate the part of the retina he or she is trying to observe" in the introduction and add a separate section on the subject explaining the physics, possibly including an illustration.

PeterJanRoes (talk) 08:09, 24 October 2019 (UTC)

References

Overwhelming Article Lead

The lead to the article is extremely overwhelming. From just the linked keywords in the section, it's clear that it goes well beyond a simple introduction to the organ, i.e. describing its function and noting its potential variations (which, of course, are expounded upon in the rest of the article's sections). Highly suggest that this part of the article be edited for clarity and brevity, and the more detailed statements moved to relevant sections. 2600:1700:6A96:60:89BA:161A:64FB:A3A7 (talk) 14:47, 30 April 2020 (UTC)

A suggestion: Reverting the additions made with this edit would go a long way toward fixing the problems stated above. --DB1729 (talk) 16:17, 30 April 2020 (UTC)

 Done [1] --DB1729 (talk) 16:20, 30 April 2020 (UTC)

Semi-protected edit request on 15 December 2020

would you please: allow me to edit this article. I want to translate it to Arabic. Nawafkassab2000 (talk) 01:08, 15 December 2020 (UTC) --Nawafkassab2000 (talk) 01:08, 15 December 2020 (UTC) Nawafkassab2000 (talk) 01:08, 15 December 2020 (UTC)

 Not done: this is not the right page to request additional user rights. You may reopen this request with the specific changes to be made and someone will add them for you, or if you have an account, you can wait until you are autoconfirmed and edit the page yourself. Melmann 13:33, 15 December 2020 (UTC)

The pupil IS NOT a black hole

I think the first phrase of the article has no sense.

Holes can't have colorations of any kind. A hole is just a gap, a cavity, and any color that could have is just related to the medium it is on (and its transparency) and the light reflection by any material beyond the hole, but not the hole itself that can't reflect, or capture, any light by itself and, so, can't have any color.

I think it should just say "The pupil is a hole".

The only reason I could find to leave it as is it is to give and idea to the reader that is that "black" thing what we have in the eye... but it is not black in first place, so creates misconception. — Preceding unsigned comment added by Wikipuh (talk • contribs) 00:46, 24 January 2021 (UTC)