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Author Topic: Would we be able to see further if we had bigger eye-balls?  (Read 24888 times)

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?  :o


 

Offline lightarrow

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Would we be able to see further if we had bigger eye-balls?
« Reply #1 on: 12/04/2009 11:19:41 »
Would we be able to see further if we had bigger eye-balls?  :o
Do you want to replace your eye-balls with watermelons?  ;D
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #2 on: 12/04/2009 11:49:15 »
Well, if it'll help me see better then YES!
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #3 on: 12/04/2009 12:09:23 »
Perhaps I have not explained myself properly? I was thinking if we had a bigger lens would we be able to see further (i.e, have higher visual acuity)?
 

Variola

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Would we be able to see further if we had bigger eye-balls?
« Reply #4 on: 12/04/2009 13:09:33 »
Perhaps I have not explained myself properly? I was thinking if we had a bigger lens would we be able to see further (i.e, have higher visual acuity)?

I think its more to do with the structure than the actual size, falcons and other birds of prey can spot small rodents hidden in the grass from way up high, yet their eyes are quite small.
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #5 on: 12/04/2009 13:11:24 »
Thank you for your comment. :)
At least we're getting somewhere. ::)
 

Offline Yomi

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Would we be able to see further if we had bigger eye-balls?
« Reply #6 on: 12/04/2009 13:17:28 »
We can say that size doesent really matter in sense organs I think Hawk or an Eagle can point out their prey from high distance wven the diametre of eyeballs is just about 1-2 cms!!!!! Quiet amazing creatures....... ::) ::) ::) ::) ::)
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #7 on: 12/04/2009 13:18:29 »
So what are they doing different to us that makes them see better?
 

Variola

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Would we be able to see further if we had bigger eye-balls?
« Reply #8 on: 12/04/2009 13:18:46 »
We can say that size doesent really matter in sense organs I think Hawk or an Eagle can point out their prey from high distance wven the diametre of eyeballs is just about 1-2 cms!!!!! Quiet amazing creatures....... ::) ::) ::) ::) ::)




There is an echo in here... lol
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #9 on: 12/04/2009 13:19:45 »
And I said we were getting somewhere? No? :D
 

Variola

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Would we be able to see further if we had bigger eye-balls?
« Reply #10 on: 12/04/2009 13:28:55 »
http://videos.howstuffworks.com/hsw/21716-birds-of-prey-the-eagles-eye-test-video.htm

Run it along towards the end of the video,till about 3.30, more of an explanation on how the eagle's eye works.

Apparently their eyes are big for their body ratio, if ours were the same size they would be as big as oranges. They also have a large iris,which allows a bigger picture to be projected onto the retina.On the retina there are light sensitive receptors called cones, which code for colour and detail. Eagles have 600,00 cones per sq mm, 4 times as many as humans.
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #11 on: 12/04/2009 13:30:35 »
Okay, forgetting about the cones for a second. If we had eyes the size of oranges our vision would be improved right? :)
 

Offline graham.d

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Would we be able to see further if we had bigger eye-balls?
« Reply #12 on: 12/04/2009 13:54:14 »
Well the size of the aperture would enable better seeing in low light levels, though the lens has to be more complex to prevent aberrations and worse acuity. But generally, if the eyes were bigger it would enable a greater density of receptors and greater light gathering capability. I guess we have evolved eyes that are adequate for our use. It would be hard to see how a complex lens could have "evolved".
 

Offline lightarrow

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Would we be able to see further if we had bigger eye-balls?
« Reply #13 on: 12/04/2009 17:32:56 »
Okay, forgetting about the cones for a second. If we had eyes the size of oranges our vision would be improved right? :)
At least this is what astronomers must have thought, otherwise we can't explain why they have constructed even greater telescopes... [8D]
 

Offline graham.d

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Would we be able to see further if we had bigger eye-balls?
« Reply #14 on: 12/04/2009 18:46:18 »
In astronomy it is important to have a very large aperture because the light levels are extremely low. You can also avoid aberrations by using a parabolic reflector. This concept has never evolved naturally - I blame biologists :-)
 

Offline LeeE

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Would we be able to see further if we had bigger eye-balls?
« Reply #15 on: 12/04/2009 19:39:21 »
Basically, what graham.d has said.

The question is actually rather mis-phrased.  What I think it should have said is "would bigger eyeballs increase the resolution of our eyes?  After all, we can all see the same 'distance'.

There are two factors at play here; the lens and the image-detector.

Assuming the same field of view, if the larger eyeball has a larger image area but the same density of photo-receptors as a normal eyeball then there will be more total receptors across the image area in the larger eyeball, increasing its resolution.

However, a larger lens just allows more light through, making the image brighter.  Even with our normal eyeballs though, unless it's pretty dark, the iris is normally contracted to reduce the amount of light entering the eye because it would otherwise be too bright.  With the same photo-receptors in a larger eye then, the iris would still have to contract to the point where the light levels reaching the receptors is the same as for a normal eye, so in bright light the size of the larger lens in the bigger eyeball has to be reduced anyway.

Another relevant factor are the imperfections in the lens.  If the number of imperfections in the lens is the same per unit area then the larger lens will have more imperfections in it, which will reduce it's resolution compared with a smaller lens.
 

Offline lightarrow

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Would we be able to see further if we had bigger eye-balls?
« Reply #16 on: 12/04/2009 21:27:12 »
In astronomy it is important to have a very large aperture because the light levels are extremely low. You can also avoid aberrations by using a parabolic reflector. This concept has never evolved naturally - I blame biologists :-)
Ok, let's say you want to make observations in a clear, bright day. Assuming the same kinds of lens qualities, would you choose a little or a bigger telescope/binocular for a greater resolution?
 

Offline graham.d

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Would we be able to see further if we had bigger eye-balls?
« Reply #17 on: 12/04/2009 21:51:51 »
If you are talking about a simple, single lens, then it would be fairly small. Not so small as to get distortions because of diffraction, but big enough to capture an appropriate amount of light for the sensitivity of the sensors. 35mm camera design over the years is a good example. A simple single lens of focal length of (say) 50mm gives just about acceptable performance with an aperture of f4.5. Better lenses developed in the early 20th century (like the Tessar lens) comprised 4 elements and worked well at f2.8. Modern many element lenses are good at f1.4 or wider. All these lenses are optimum for resolution at a stop or two smaller aperture and all the lenses will start to have diffraction problems at f22 of smaller. 
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #18 on: 13/04/2009 03:59:44 »
That's fascinating stuff. :)
You want me to change the title of the thread LeeE (even though I know you have a thing against it)?
 

Offline stereologist

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Would we be able to see further if we had bigger eye-balls?
« Reply #19 on: 13/04/2009 04:31:57 »
Take a look at the eye of the horseshoe crab. This creature has mastered 3 methods that allow the eye to perceive images over an amazingly wide range of light intensities.
 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #20 on: 13/04/2009 12:41:04 »
Okay, so if you were to sum up the answer to the question in three sentences, what will it be?
 

Offline graham.d

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Would we be able to see further if we had bigger eye-balls?
« Reply #21 on: 13/04/2009 13:35:58 »
Can I write very long sentences? :-)

It is really hard to do this because your question needs many caveats to answer it properly.

1. Simply making the eye bigger does not help because it needs more doing to it, such as adding more receptors and/or a more complex lens.

2. If we assume that the size of an individual receptor (like a pixel) is fixed and that the basic eye design should not change, then making the eye bigger will create a larger area of receptors for the same field of view and, providing the brain is changed to cope with the information, will give a higher resolution, thus enabling a proportionate improvement in the distance vision with the same light levels.

3. The same effect could be achieved by keeping the eye the same size and design but having more, and smaller, receptors; this is why a 20 Mega-pixel camera has better resolution than a 4 Mega-pixel camera.


The eye and brain are very complex in how they work together. An eagle, for example, has much better resolution than a human eye, not because of the size of the eye compared to a human eye, but because of the size, structure and speciality of the receptors (about 5x the density of the human eye). They have quite poor night vision though. Owls, in contrast, have very good night vision and have very large eyes compared to their head size. The eyes are fixed in their heads hence the remarkable, but necessary, head movements owls can achieve. Their brain sorts out the parallax problems that arise. All designs, whether created by humans or formed by evolution, are compromises that achieve what they need to for optimum use. Simply changing one of many features will alter the performance in one area at the expense of another.

 

Offline Chemistry4me

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Would we be able to see further if we had bigger eye-balls?
« Reply #22 on: 13/04/2009 13:42:29 »
Wow, thank you kind Sir. :)
You've made it fairly clear for me to see. ;D
I don't think anyone can beat that.

 

Offline Don_1

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Would we be able to see further if we had bigger eye-balls?
« Reply #23 on: 13/04/2009 14:04:06 »
I guess we have evolved eyes that are adequate for our use.

I think this is the best answer to the question 'Why aren't our eyes as good as an Eagle's?' A bird of prey needs to fly high to enable it to see a very wide field, but it's eye must be capable of spotting prey from such a distance. Being able to see so well at great distances would be of no benefit if you could not then launch an attack at high speed. Since birds of prey do have the ability for high speed attack, the high resolution vision is supported. The two capabilities are necessary to be of use to each other. One without the other would be pointless.

Since humans have never had the capability of high speed attack on our prey, or the necessity, such high resolution vision would be pointless and could infact be counterproductive. Too much detail could lead to confusion.

As to this thread's question, I should think a larger eye would not be necessary for improved long distance vision. Perhaps an improved lens and retina might be all that would be required, along with an improved 'processor'.
 

Offline lightarrow

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Would we be able to see further if we had bigger eye-balls?
« Reply #24 on: 13/04/2009 14:59:35 »
As to this thread's question, I should think a larger eye would not be necessary for improved long distance vision.
Certainly, I agree with it. But it depends on how much "long distance". If you want to increase that distance a lot, before or less you'll have to increas the eye's dimensions.
 

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Would we be able to see further if we had bigger eye-balls?
« Reply #24 on: 13/04/2009 14:59:35 »

 

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