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Eye pupil size, eye color, DNA, Mydriasis

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#1 TomCorbett

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Posted 26 August 2013 - 05:33 PM

WELLLLLLLLL...

I have been a CN member on and off for seven or so years. I have both binoculars and scopes. During those seven years I have often read threads about the terrors of the deep--the 7mm exit pupil. Well, all of this optical savvy and graphs and charts and big words are nice. I tip my hat to the optical engineers.

HOWEVER...

During all of these warnings about the terrors of the deep--the 7mm exit pupil--I continue to grab binoculars (and scope/eyepiece configurations) that give me large exit pupils for my large Scottish baby blue eye pupils. And I must say that I am not sorry--I just see better through binoculars and scope/eyepiece configurations with large exit pupils.

What color are your eyes?

My eye doctor said she has seen in her patients a tendency for blue-eyed eye pupils of North European descent (DNA) to have larger dark-adapted eye pupils; and her patients with baby blues retain their oversized dark-adapted eye pupils to a much older age than her patients with non-blue eyes.

What color are your eye pupils?
Where on the globe did your ancestors live?
How goes it with your eye pupil DNA?

SOOOOOOO...

Do my large eye pupils mean that I come from good Scottish Clan bloodlines?

Or, as a result of a head injury I suffered at age 14, (or some other biological mishap), do I frequently suffer from an optical condition called Mydriasis?

Did Edward Emerson Bernard, reputed to have one of the best observing eyes in the history of recent astronomers, suffer from Mydriasis?

It is not always about optics. Sometimes it is very much about genetics and biology.

:grin:

#2 Stacy

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Posted 26 August 2013 - 05:37 PM

I have blue eyes, like my dog. :)

#3 JustaBoy

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Posted 26 August 2013 - 08:11 PM

Well Bob,

I've had many head injuries so I'm gonna vote for that... :shocked:

With me however, I think a lot of it has to do with 7x50s and 10x70s having 'normal' field eyepieces, while they almost always seem to find the room for the ragged field wide fields in the higher powers.

Why oh why doesn't someone make a good 7x50 or 10x70 with 5 element eyepieces and 50° AFOV? - Now that would be really nice!

Or do they? BA8 10.5x70???

Please show me no field unless it is fine!

-Chuck

#4 Jon Isaacs

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Posted 26 August 2013 - 10:15 PM

What color are your eye pupils?
Were on the globe did your ancestors live?
How goes it with your eye pupil DNA?



My ancestors are basically northern European, my mother's side was Swedish and my father's side was English/Scottish/German/etc.

My eyes are blue and a recent attempt at measuring my dark adapted pupil seemed to indicate 7mm. I am 65 years old.

Jon

#5 steve@37n83.9w

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Posted 26 August 2013 - 10:17 PM

WELLLLLLLLL...

I have been a CN member on and off for seven or so years. I have both binoculars and scopes. During those seven years I have often read threads about the terrors of the deep--the 7mm exit pupil. Well, all of this optical savvy and graphs and charts and big words are nice. I tip my hat to the optical engineers.

HOWEVER...

During all of these warnings about the terrors of the deep--the 7mm exit pupil--I continue to grab binoculars (and scope/eyepiece configurations) that give me large exit pupils for my large Scottish baby blue eye pupils. And I must say that I am not sorry--I just see better through binoculars and scope/eyepiece configurations with large exit pupils.

What color are your eyes?

My eye doctor said she has seen in her patients a tendency for blue-eyed eye pupils of North European descent (DNA) to have larger dark-adapted eye pupils; and her patients with baby blues retain their oversized dark-adapted eye pupils to a much older age than her patients with non-blue eyes.

What color are your eye pupils?
Were on the globe did your ancestors live?
How goes it with your eye pupil DNA?

SOOOOOOO...

Do my large eye pupils mean that I come from good Scottish Clan bloodlines?

Or, as a result of a head injury I suffered at age 14, (or some other biological mishap), do I frequently suffer from an optical condition called Mydriasis?

Did Edward Emerson Bernard, reputed to have one of the best observing eyes in the history of recent astronomers, suffer from Mydriasis?

It is not always about optics. Sometimes it is very much about genetics and biology.

:grin:



Nice post that raises some interesting questions. I've always been blessed with excellent night vision as in walking around in the stomp dark while camping etc. at night and never needing a light in order to see well enough to walk around. I also spend a lot of time glassing for wildlife from dusk to dark and spend several nights a week under the stars.

I also regularly float many of the local streams fishing many hours at night for small mouth bass and rarely turn my headlamp on. I sometime wonder if there is something about the old adage "use it or lose it" as far as a persons ability to adapt to seeing in the dark.

I'm sure heredity also plays an extent to some part because I remember my father also had excellent night vision and come to think of it he was also blue eyed as I am. I'm also a big fan of large exit pupil binoculars not just for their low light performance but also because I just find them so easy to use and love the views they provide. As a matter of fact I think my next purchase will either be a 10x70 IF or a center focus 7x50.

Steve

#6 Tony Flanders

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Posted 27 August 2013 - 05:52 AM

My eye doctor said she has seen in her patients a tendency for blue-eyed eye pupils of North European descent (DNA) to have larger dark-adapted eye pupils


Just a minor correction: You are talking about the color of the iris, not the pupil. Pupils are black.

It would make sense for Northern Europeans to have larger pupils than most, since Northern Europeans have many other exotic adaptations to their exceptionally cloudy climate -- notably pink skin (traditionally called "white"), which evolved nowhere else in the world.

Put another way, Northern Europeans lack the adaptations that most people have to deal with high levels of sunlight. People with blue eyes are more prone to diseases like macular degeneration, which is thought to be caused partly by exposure to sunlight.

My daughter, who is from India, can't understand why people want to wear sunglasses. She can also look at a partial solar eclipse and tell you the phase -- as can several other people from India whom I know. I can't look straight at the Sun even if I want to.

My father's ancestors were mostly from England and Scotland, and he had blue eyes. My mother's ancestors were Eastern European Jews, and she had dark hazel/brown eyes. My own eyes are hazel, and my pupils open to 5.5 mm.

I'm not at all convinced that there's a significant correlation between pupil size and night vision, astronomical or otherwise.

#7 Jon Isaacs

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Posted 27 August 2013 - 06:45 AM

I'm not at all convinced that there's a significant correlation between pupil size and night vision, astronomical or otherwise.



When you add it all up, I have to agree... There are few situations where a little magnification and a dimmer image does not show more detail. Add in the aberrations that result from a 7mm entrance pupil...

Jon

#8 kcolter

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Posted 27 August 2013 - 07:06 AM

Pupil size=aperture=light gathering capacity. Dark adaptation is a chemical event that occurs in the retina. There is another factor that to my knowledge goes without a name, it would have to do with one's ability to sort signal from noise at the level of optical cortex, and in the processing centers "above" the optical cortex. I suspect that the Stephen O'Mearas of the world excel at seeing the really dim and the really subtle things at the eyepiece because of a superior training of this "visual associative cortex" in the brain. I suspect that really good deep sky observers have a superior ability to sort signal from noise that allows them to pick out faint fuzzies. It's easy to measure pupil size and much harder to measure one person's retinal dark adaptation ability compared to another, harder still to measure one person's visual associative skills relative to another, other than to take them to the eyepiece and see who sees the subtle faint fuzzy and who doesn't.

#9 Jon Isaacs

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Posted 27 August 2013 - 07:28 AM

Pupil size=aperture=light gathering capacity.



Kim:

This only applies if the exit pupil is sufficiently large, otherwise, a larger pupil collects no more light than a smaller but sufficiently large pupil...

Some good stuff about the visual cortex, this is why experienced observers see more. One other factor, transmission of the eye's lens.. cataracts etc.

Jon

#10 TomCorbett

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Posted 27 August 2013 - 08:10 AM

These photos came across my facebook page today. I thought I would share the links in this thread. Cat with dark-adapted eye pupils (source: Different Photos)

Eye pupil of an Eagle Owl (source: Scottish Owl Center)Enjoy.

#11 kcolter

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Posted 27 August 2013 - 08:36 PM

Jon
You are absolutely right about pupil size greater than the exit pupil of the instrument collecting no more light than a pupil equal to the exit pupil of the eyepiece on the instrument. I was just trying to make the point that dark adaptation is a retinal event independent of pupil dilation. The point about cataracts is well taken as well. I have read that the lens of a 65 year old transmits only one third the light transmitted by the lens of a child. By the time we get to the stage of life where we are fascinated by the night sky, we've already lost some of our ability to see it.

#12 Jon Isaacs

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Posted 28 August 2013 - 07:31 AM

I was just trying to make the point that dark adaptation is a retinal event independent of pupil dilation. The point about cataracts is well taken as well. I have read that the lens of a 65 year old transmits only one third the light transmitted by the lens of a child. By the time we get to the stage of life where we are fascinated by the night sky, we've already lost some of our ability to see it.



Kim:

:ubetcha:

Pupil dilation happens during dark adaptation but it's relative importance is minor at best in comparison to all the other things that happen.

I am intrigued by the whole cataract thing and general loss of transmission...

Jon

#13 dan_h

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Posted 28 August 2013 - 09:01 AM

I am intrigued by the whole cataract thing and general loss of transmission...

Jon


I am plagued by the whole cataract thing and general loss of transmission...

I suspect it won't be long before I am looking for replacemnet parts.

dan

#14 smart

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Posted 28 August 2013 - 09:17 AM

Aphochromatic triplet retina replacements are on our horizons! There is still hope for us oldsters. Harold in Oregon

#15 Binojunky

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Posted 28 August 2013 - 12:35 PM

Eye care and regular check ups are more important than DNA, heritage etc in my opinion.
As my eyes aged regular check ups caught early I,m glad to say Glaucoma, retinal tears and cateracts, DA.

#16 Jon Isaacs

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Posted 28 August 2013 - 02:52 PM

Eye care and regular check ups are more important than DNA, heritage etc in my opinion.
As my eyes aged regular check ups caught early I,m glad to say Glaucoma, retinal tears and cateracts, DA.


Good point... It's been a while since I had a eye checkup...

Jon

#17 Man in a Tub

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Posted 29 August 2013 - 01:15 AM

My daughter, who is from India, can't understand why people want to wear sunglasses. She can also look at a partial solar eclipse and tell you the phase -- as can several other people from India whom I know. I can't look straight at the Sun even if I want to.


My eyes are not greener with envy. Your daughter and the several other people from India are as much at risk as anyone else on this planet.






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