Talk:Adaptation (eye)

Contrast ratio

"However, in any given moment of time, the eye can only sense a contrast ratio of one thousand". I remember reading somewhere, don't remember where, that the human eye could only sense a contrast ratio of 1:100 at a given moment. Whichever is correct, we need to find a reference for it. Kaldari (talk) 18:13, 24 September 2009 (UTC)

This needs correct info badly.

in https://en.wiki.x.io/wiki/Human_eye#Dynamic_range :

[16] https://books.google.fi/books?id=DR9UyqLkgH8C&pg=PT110 p.92: "The eye is capable of registering a contrast range of approximately 1000:1." No references to this claim is given.

[18] https://books.google.fi/books?id=LL5orppYlJsC&pg=PA1 p.1: "Humans can see detail in regions that vary 1:10^4 at any given adaptation level." No references to this claim either.

Very Poor

Some work needs to occur. In between this and the Night Vision article, you learn nothing. To add:

Comprehensive information on, for instance, ability percentages of different animals.84.92.169.252 (talk) 15:21, 3 June 2010 (UTC)

Rephrasing and elaboration required

I presume the following would be crucial to a basic understanding of adaptation to dark.

"Inhibition by one neuron on another is just as important as activation in synapses. Together with the bleaching of a rod or cone pigment, merging of signals on ganglion cells are inhibited, reducing convergence. Alpha adaptation, i.e. rapid sensitivity fluctuations, is powered by nerve control."

Instead of actually increasing the reader's wisdom, this only servers to bewilder them. What is alpha adaptation, is the control voluntary, what is convergence, why are signals merged, is bleaching done in the dark, why is inhibition important?88.112.37.71 (talk) 13:09, 25 October 2011 (UTC)

Not good

What about animal eye adaptation? — Preceding unsigned comment added by 74.131.171.6 (talk) 18:28, 30 January 2013 (UTC)

I noticed all the tests on adaption is getting fairly old some 1980~ 30+ years ago.

(Sorry for my english, im norwegian)

However i wasnt able to see how many people were actualy in these tests... how realistic are these tests? have there been controll tests to verify.. i mean the grey area in the test showing 80% of the people% had a pretty large radius difference, up to 3-4 minute faster, not counting those 20% whit faster or slower where the range is increased even more, and it does look like most of the reseptors for dark vision sets inn in about 10 minutes, then the other 20 minutes its slowly adapting more... and even if i count those 10 minutes, it still looks to be lots of people getting most of their dark vision in 5...

However i still find the problem of how many was in the test... i mean... i know people who claim their eyes addapt in about 2 minutes to very low light levels, from a bright room.. and i can say myself i also feel like i have realy fast dark vision.

And then again i suspect this test has less than 4000 people or and most of them must be originating from same contry as the test came from, wich means their eyes are probebly more addapted to how many months of the year theyr exposed to darkness.

Like for example me, im from norway, and here it feels like its dark some 5-6 months of a year and cant say its much light troughout the summer.

Now take sombody for example from Egypt, daylight probebly every day.... and this might have a major impact...

This is why i suspect the test has less than 4000 people.. does anyone have any actual numbers, or and why isnt this on the wiki page as this would be important for accurasy of the topic of how long it takes to addapt.

Seeing the links below where i followed them, i couldnt seem to find any number of people involved..

again, terrible sorry for my english, and i hope that doesnt impact the very important question.

Proposed merge with Accelerating Dark Adaptation in Humans

Accelerating Dark Adaptation in Humans seems to spend a lot of its content covering the same ground as Adaptation (eye), and actually covers some aspects (night blindness, vitamin A, evolutionary context, use of red filters) that the latter article omits. Stripped of the excessive detail about vitamin A, the actual content about accelerating adaptation with anthocyanins would, I think, fit into a single section of Adaptation (eye) without overwhelming it. McGeddon (talk) 13:07, 13 June 2016 (UTC)

• support merge. Vitamin A content is also sourced to non-MEDRS sources and should be stripped. Jytdog (talk) 18:00, 4 January 2017 (UTC)
• Alternative idea... There's a lot of good material at Accelerating Dark Adaptation in Humans that we should try to preserve, but that's a weird article title. What about we re-name it dark adaptation (which currently re-directs here) and have it as a more detailed article alongside the broader adaptation (eye)? Bondegezou (talk) 18:21, 4 January 2017 (UTC)
• Support merge: the two sides of adaptation, light and dark adaptation, are already discussed on this page. In the case of dark adaptation this is: Adaptation (eye)#Dark adaptation. So, its seems counterproductive to move the current Accelerating dark adaptation in humans page to dark adaptation. Rather, accelerating adaptation concepts would fit will within the existing Adaptation (eye)#Dark adaptation section, with other more general material (not specific to 'accelerating') should be merged with overlapping material elsewhere in that section. Klbrain (talk) 13:20, 2 March 2018 (UTC)

 Done Klbrain (talk) 12:47, 18 March 2018 (UTC)

Adaptation duration

The article is misleading when it says eyes are fully adapted after a half hour. There are plenty of science experiments that disprove that. University of Illinois states numerous experiments where the human eyes can see flashes of light consisting of 3 photons and possible less in long term exposure to darkness. In astronomy it's well known that you should allow your eyes to adapt to darkness for at least two hours. It's not that retina size changes much, but there are actual changes occurring to the retina as it's exposed to darkness over the hours and even days. Here's the link, http://research.physics.illinois.edu/QI/Photonics/pdf/PWDec16Holmes.pdf — Preceding unsigned comment added by 108.93.181.106 (talk) 17:44, 5 August 2017 (UTC)

Yes, it should say "mostly adapted", there is some further adaptation going on after that. After all it is an asymptotic behaviour. I have changed it to 'two hours' and added the reference. Strasburger (talk) 11:37, 20 April 2019 (UTC)

Unaided night vision training

Please add information about unaided night vision training and applications, such as military watches at sea in World War 2.-73.61.15.43 (talk) 16:07, 11 December 2017 (UTC)

The pupillary light reflex is not adaptation

In this subject of a dilated fundus examination, the eye on the left is undilated, and the eye on the right has been dilated using a mydriatic eyedrop.

The introductory image was misleading since the pupillary reflex is not what is meant by adaptation. I have moved the image here in case somebody wants to do something with it. Strasburger (talk) 11:44, 20 April 2019 (UTC)

Limited in resolution

Lede has "Night vision is of lower quality than day vision because it is limited in resolution ". AFAIK the resolution of color sensitivity is a quarter or less of low luminosity resolution. What does the cited reference really say? 2003:F5:6F05:2A00:ADA5:8506:2DD2:A1D7 (talk) 15:13, 31 October 2020 (UTC) Marco PB

I don't have the reference but cannot see what is wrong with the cited statement (which is standard in textbooks): Night vision is based on rods and the density of rods in the fovea is much lower than that of cones. See e.g. the graph "Distribution of rods and cones" in Photoreceptor cell.

Concerning the second statement (which is also correct), the resolution of color sensitivity is different from (and much lower than) cone density, even though color perception is based on cones.

Strasburger (talk) 11:38, 1 November 2020 (UTC)