Questions regarding how the brain interprets information from the eyes. Consider using the "eyes" tag for discussion of eye anatomy, physiology and evolution.
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1answer
33 views
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 ...
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0answers
25 views
What processes are responsible for focusing on an image only seen by one of the eyes?
When a person is spying from around a corner with only one eye, it's rather easy to ignore the other eye's image, since it's probably much darker, because one usually spies around a corner standing ...
1
vote
1answer
53 views
Why are trichromat cone cells unable to sense ultraviolet and infrared radiation?
I understand that cone cells vary in the color they sense, is this because of wavelength, frequency, something else, or a combination of the previous? I also understand that tetrachromats can see an ...
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2answers
61 views
What gives observable light its colors? [duplicate]
I know that difference between different colors of light is difference between their wave length but I don't know what gives beautiful colors (like rainbow colors) to different wave length of ...
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0answers
22 views
Perception of distant lights without glasses
I am fairly short-sighted and wear glasses pretty much all the time. Naively, I would expect that when I take my glasses off, the image I see should look very much the same as as a photograph that's ...
4
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3answers
70 views
Is it technically possible to make someone see something when their eyes are closed?
I'm writing a little article and need any information about how human vision works and latest
technologies and discoveries around. Actually its not a professional article. Its for a group of my ...
1
vote
1answer
26 views
What is the brightest color a light source that only emits blue frequency light can achieve?
Let's say there is a luminous light bulb that only emits blue light, and you (or a camera if you prefer) look at it from a close distance. Will the maximum brightness perceived not have any "white" to ...
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vote
1answer
30 views
Is there an optimal illumination level for human habitats/workplaces?
I know of melanopsin, a photo pigment in mammal eye that helps regulate circadian rhythms. It responds most strongly to blue spectrum light. There have been experiments that demonstrated that ...
6
votes
2answers
95 views
What is the difference between a circular and a cat's-eye pupil?
I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on ...
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0answers
19 views
HSL Lightness vs Eye sensitivity
In a monochromatic spectrum, is the human eye equally able to distinguish between lighter colors just as it is in distinguishing between darker colors? I mean is there really a linear relationship ...
7
votes
2answers
102 views
Does every human eye see the same visible spectrum?
It is said that human eye can see light with wavelength approximately between 400nm and 700nm.
Are these upper and lower bounds same for every human? If not, what are the means and standard ...
4
votes
1answer
80 views
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 ...
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vote
1answer
107 views
Does coloring affect the perception of depth?
I have a question about the mechanics of human vision which may be as much of a physics question as it is a biology/physiology question. I noticed that if I try to imagine a clear blue daytime sky ...
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2answers
60 views
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?
3
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0answers
88 views
Why does vision go blurry after microscope use, and how to prevent it?
After using a binocular microscope recently for about 20 minutes, my vision went blurry and for an hour or so it was much harder to read small text. This occurs to a (far) lesser extent whenever I use ...
8
votes
1answer
116 views
What are the “stars” we see after a bump on the head?
Sorry if this might appear funny. When I close my eyes for a longer time, and suddenly open it, I see some twinkling white small circles, and when i concentrate on anyone of them it disappears, as ...
4
votes
1answer
194 views
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
...
6
votes
2answers
756 views
Which shades/hues of color are easiest to distinguish for humans?
I'm trying to represent data graphically and am using a variation of hue/lightness to distinguish one data point from the next. I would like to use a color that would allow me to convey most ...
2
votes
1answer
97 views
Can visual acuity be improved?
Is it possible to completely cure myopia using natural methods (i.e. not with Lasik etc.)?.
I have seen websites claiming that exercising the eyes will help improve eyesight.
Is this true?
4
votes
1answer
121 views
Why does squinting allow you to see clearer objects?
How does squinting alllow one to see clearer pictures? What are the harmful effects?
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1answer
31 views
Does retinal detachment happen more frequently at night?
My understanding and experience is that during the night photoreceptors are less tightly coupled to the retinal pigment epithelium. Does this make it more likely for a retinal detachment to happen at ...
13
votes
4answers
360 views
Why did life not evolve to use radio?
We use electromagnetic communication everywhere these days. Cell phones, wifi, old-school radio transmissions, television, deep space communication, etc.
I'm curious about some of the possible ...
8
votes
1answer
221 views
Why does this illusion work?
This is another image I found on Google+
All lines are absolutely straight, parallel and perpendicular but why does it appear to have a curvature?
Related: How does this illusion work?
2
votes
1answer
606 views
What negative effects can pinhole glasses have on the body?
While shopping in the local supermarket yesterday, I was surprised to find this display on one of the shelves.
I also realize that I should have taken a pamphlet with me, as well as a picture of ...
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0answers
109 views
How do optical illusions work? [closed]
Hello fellow investigators
I have two questions about optical illusions
1) A photo mosaic is something like this http://i.stack.imgur.com/Pzplp.png
What are the optical principles behind our eye ...
4
votes
0answers
36 views
Does a mydriatic drug neutralize the action of a miotic?
If a person were administered a mydriatic, would the subsequent application of a miotic neutralize the action of the former? If the sequence were reversed would a mydriatic neutralize the effect of a ...
4
votes
1answer
660 views
How does this illusion work?
I found this image on Google+
If you shake your head you can see a portrait of a person. Can anyone explain how the image is constructed in the brain?
12
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4answers
1k views
Does red light preserve your night vision?
A number of companies have started marketing LED lamps that can be switched to a red mode. The claim is that red light is less harmful to one's night vision. Given that our eyes are less sensitive to ...
16
votes
1answer
443 views
Why do stars disappear when I look at them?
I've noticed that when I'm out at night stars seem to vanish when I focus on them. I assume the reason is physiological and not astronomic. Why does this happen? I would expect that things would be ...
7
votes
2answers
244 views
How do we know the brain flips images projected on the retina back around?
Why do we turn images upside down again rather than dealing with them directly, still vertically rotated after passing through our lens?
I don't see how that would cause any problems, and how we'd ...
9
votes
4answers
695 views
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?
7
votes
1answer
100 views
What causes light to be brighter in the corner of the eyes?
I have noticed when in a dark room light and color seem to be brighter and more intense in the corner of my eyes. For example the light that comes from my digital clock seems like a dark pink when I ...
9
votes
2answers
280 views
Do insects with compound eyes have depth perception?
Do insects with compound eyes have depth perception? They fly as if they do, but their eyes are so close together it seems like the image would be 2 dimensional.
8
votes
1answer
148 views
Which organism has the sharpest vision?
Which organism has the sharpest vision in terms of distance and spectrum. Please propose any other useful measure.
11
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2answers
283 views
When did vision evolve for the first time?
Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a ...
10
votes
2answers
157 views
Can a color-deficient person be made to visualize the missing colors?
Hope this is within the scope of this site.
Color-deficient persons lack the cells in their retina needed for differentiating some (or all) colors.
However, the part of the brain that actually ...
37
votes
3answers
567 views
Is there a reason why human eyesight and plants make use of the same wavelength of light?
The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the ...
