Biology Stack Exchange
Biology Stack Exchange

Questions tagged [vision]

Questions regarding how the brain interprets information from the eyes. Consider using the "eyes" tag for discussion of eye anatomy, physiology and evolution.

The tag is for questions about how the brain and eyes combine to give and interpret signals to give vision, how an organism processes the electrical signals it receives from its visual organs.

For questions on eye and brain anatomy, physiology and evolution see the and tags respectively.

331 questions
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Seeing strange things in light

I have noticed that if you look directly at tubelight (I have only white ones in my home) and close your eyes little, you see little random shaped colourless things sometimes with slow speed and sometimes with falling down. They are shaped like…
evil999man
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15
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Why can cones detect color but rods can't?

I don't know if this question applies to only humans but why can cones see much greater detail than rods? Is it possible to have a rod that can detect light intensity and color?
Gabriel Fair
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9
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1 answer

What gives things their colour?

My 6 year old daughter asked me 2 biology-related questions yesterday and I tried my best to answer them with the aid of YouTube videos. One of the questions (I may post the other one too) was How do we see colour? I showed her a video on YouTube…
Sachin Kainth
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7
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2 answers

Can the eye distinguish between pure and composite colours and how do we measure this?

Red light plus green light makes yellow light. Suppose I shone a pure red light, say 650nm, onto the same spot as a pure green light, say 550nm. The eye sees this two-peak spectrum as yellow. This presumably means we are tricking the eye, since a…
spraff
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6
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3 answers

What is the equivalent of shutter-speed in Human eye?

I just learned that in video cameras, every frame of the video has its own shutter speed. And I know how frame-rate in human eye works out, well, not completely, hence the question. http://en.wikipedia.org/wiki/Frame_rate The human eye and its…
laggingreflex
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4
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2 answers

Animal UV vision

It is reasonably well known that many species, such as bees and some types of birds as examples can see into the ultraviolet (UV). How is the structure of their eye different to humans to allow this? Also, how are they shielded from some of the…
user3795
4
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1 answer

Why do we squint?

Recently, I was having an eye exam and admitted to squinting my eyes to sharpen blurred edges. Later, while waiting for the dilation to set in, my brother (a would-be pharmacist fresh off an anatomy course) was telling me about how vision works. As…
Aarthi
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4
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Why do we see a different color when we mix two colors?

The compounds responsible for a color do not change when they are mixed with another material. The same compounds are there after mixing. However, when we mix colors such as blue and yellow we see green. BUT we are able to tell where a color starts…
CoffeeIsLife
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4
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How far can birds see?

I have heard that birds have exceptional eyesight. How far does this mean they can see? What's the resolution like? Are we talking about just vague shapes or something like, at 100 feet, seeing individual hairs on a dog's fur coat? I've also read…
Stan Shunpike
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3
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Understanding David Chalmers claims on direct mappings between our vision and visual awareness systems

I am reading the popular 1995 paper "Facing Up to the Problem of Consciousness" by David Chalmers [PDF] as part of my philosophy course. I am only asking about the relevant vision related claims Chalmers makes, so you need not read the full…
Gaurang Tandon
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3
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1 answer

Does 405 nm light set off phosphorescence in the eye?

While playing with a blue/violet laser (5 mW, 405 nm) tonight, I noticed that on dark, non-fluorescing surfaces, the beam reflection was trailed by what looked like a dimmer reflection of the beam. The effect was most easily observed when I moved…
Wayfaring Stranger
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The Eye, and Camera Lenses

How do near sightedness, farsightedness, and normal sightedness work? If the eye is accustomed to one small focal point, how can it manage a wall of light? And also, how does it process the small pinpoint that it normally does?
user3534
2
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2 answers

Possibility of orthogonal view for a creature?

Just a pure curiosity: Does there exist a creature with an orthogonal view to the world instead of perspective? What would be an optical explanation for possibility/impossibility?
Developer
2
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1 answer

How does myopia actually work?

This is potentially more or less a question about optics, but I've never been truly satisfied with any explanation that I've been given about Myopia. In fact, I almost can't even believe it. There are a million different versions of this diagram: I…
Abe Fehr
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How can eyeglasses improve vision beyond 100%?

The result of a vision test by my oculist yielded a result of more than 100% while wearing prescription glasses. I wonder, how can a person see better using eyeglasses?
Omnibus
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