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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447 views

Why does a light object appear lighter in your peripheral vision when it's dark?

So, I am not sure I can reproduce it via images, but the steps are: 1) At night, open a window and have a look at the surface of the earth 2) Suppose there's an object that reflects a tiny amount of ...
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2answers
118 views

Why don't myopic people see the world upside-down?

I found this image while reading optical instruments in physics. If we look at the uncorrected rays, we see that the image they outline gets inverted. So why don't people with myopic vision see ...
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194 views

Are these claims of “revolutionising” understanding of human vision and hearing valid?

I've started a hobby machine vision project (and posted some questions to this end on other SE sites) and on a side track, also been looking at relevant research in human vision (and partly, hearing). ...
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2answers
124 views

How does the eye know whether to focus further out or nearer in order to bring a blurry object into focus?

If the eye sees an object, but the object is out of focus, the eye could be focusing too near or too far. How does the eye (or the brain) distinguish one situation from the other? How does it know ...
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2answers
94 views

Can the human eye distinguish colors in the periphery?

In the back of my mind I have the idea that human eyes can't notice the color of objects in the far periphery, and that any subjective perception of colors is done by the brain that tries to fill in ...
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2answers
114 views

How does optogenetics work?

I am aware of the post here 'Optogenetics - How do microbial opsins work?' however it is a bit too technical for me. I am struggling to understand how the neurons can be genetically engineered to ...
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3answers
3k views

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. ...
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117 views

Was life less colorful before color vision evolved?

According to Wikipedia, we know that color-vision photopigments appeared in the common ancestors of tetrapods and fish at least 360 MY ago. Would life have been less colorful before the evolution of ...
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3answers
199 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 ...
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1answer
403 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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1answer
61 views

Can other animals see black differently?

I am not sure if this is the right place for this question, but this is a debate that has been going on between two colleagues for days and I need a resolution because it's driving me crazy. So any ...
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67 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 ...
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68 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 ...
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Would constant light or fading light be registered as more wakefulness promoting by the Supra Chiasmatic Nucleus?

During the fall and winter season, a number of people are experiencing Seasonal Affective Disorder. One of the way it has traditionally been treated is with a dedicated lightbox - a very high ...
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1answer
89 views

Retina Transplant Difficulties

Why is retina transplant not as easy as the normal eye donation and transplant (I think the latter involves the cornea ) ? This says that a new method has come up but why isnt the process similar and ...
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1answer
74 views

Do human visual functions degenerate due to genetic factors or by external factors?

Does eyesight primarily deteriorate 'naturally' due to genetics (genomic/epigenomic factors), or due to external factors such as normal wear and tear, or disease? By normal wear and tear I include ...
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278 views

What exactly is the neural receptive field?

Neural receptive fields map the spatial or temporal distribution of the data to individual neuron excitation, if I understand correctly, but I do not understand if receptive fields (especially in the ...
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62 views

Effect of closed eyes on balance?

Suppose you want to stand on one leg. Doing it eyes open is not that difficult, but doing it eyes closed seems to be difficult. Why?
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41 views

What are limitations on the number of objects the eye determine at a glance?

Take two people Sam (average human) and Jack. Jack says to Sam "I'm going to show you some skittles (or other object) and I want you to tell me as quick as you can how many I'm holding." He opens ...
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222 views

Ventral stream pathway and architecture proposed by Poggio's group

Please can you give me a very brief explanation about all functions in the ventral stream architecture summarized in this figure: This figure is from Serre et al.'s A quantitative theory of ...
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2answers
193 views

Why do our eyes “wrap” hue from UV to IR?

On the high-wavelength side of things, we see almost-infrared as reddish, with a slight tinge of magenta. On the low side, we see violet fading into the same magenta color. Why is that? You can see ...
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1answer
198 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 ...
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2answers
78 views

Why can't the human eye focus blue light?

I recently noticed that it is hard to focus on blue light sources, especially at night. When observing a blue light source, e.g. a neon sign, it looks somewhat blurry. A sign with a different colour ...
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125 views

Why do small fonts strain the eyes?

I understand that too much close reading will strain the ciliary muscles of the eyes. But what about small fonts? The contraction of the ciliary muscles is dependent on the distance not font size. In ...
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123 views

How much energy is required to blind someone?

As I understand the ravages of sunlight upon the (human) eye; the cause of ocular damage and blindness is too much energy delivered to the cones and rods that ultimately make up our eyes; so the ...
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31 views

How far can birds see? [closed]

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 ...
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25 views

Color perception vs shade perception demo

I can't seem to find one of the best demos I've seen of color vs brightness perception. It consisted of a rotating animation of earth made of red of bright red points on a dark green background. As ...
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59 views

The Operation of tuning in the S1 layer of ventral model

According to my previous question in ventral Stream pathway and architecture, I want now to get a brief example about how the S1 layer is constructed. In other words, how all the simple units are ...
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44 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 ...
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308 views

Why does vision go blurry after microscope use, and how to prevent it? [closed]

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 ...
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2answers
97 views

Parallels between pixelized image and the human retina

On Wikipedia it is explained that the human eye has a certain 'resolution'. Does this mean that the retinal image consists of pixels? If yes, what shape would these pixels have?
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181 views

What is the minimum eye?

What is the minimum eye which confers some evolutionary advantage? By minimum I mean anything less than this has no advantage whatsoever and therefore is not favored by natural selection. By eye, I ...
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74 views

Do animals exist which have great vision, but see only grayscale?

In computer vision the color information is often discarded, as most object recognition tasks seem to work just as well on the greyscale image (even better, because there is less unnecessary ...
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2answers
117 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?
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76 views

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? ...
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406 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?
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1answer
36 views

What is the difference between myopia and hyperopia?

In myopia the lens is bending the light too much even in the most relaxed state. Thus the image is produced in front of the retina. If the object comes closer the lens just adjusts a bit less than a ...
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1answer
56 views

Using perceptual adaptation for enhancing realism of VR/other entertainment

I am quite a fan of the recent oculus rift VR glasses, but it does have several flaws over normal vision, most notably a much less wide field of view, the so-called screen door effect because of too ...
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1answer
99 views

A subtle test for color-blindness [closed]

Is there a test method of proving a person being color-blind, without letting the test subject know, that he/she is being tested? E.g. showing the person cards with colored dots like depicted here is ...
2
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1answer
48 views

Like size and colour constancy, why does the brain not maintain focus constancy?

I have progressive myopia. I grew up with perfectly normal eyes but slowly started getting myopic. The thing is, my brain knows (or should know) what the world looks like -- it knows that far away ...
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1answer
82 views

Does Spinning dancer has anything to do with your eyesight

I came across the spinning dancer as part of the brain test to determine left brain vs right brain dominance. I saw the dancer is turning clockwise. The other people around me saw it turning ...
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1answer
50 views

What is the focus distance of a 3D screen?

I've thought long and hard about wheter this is the appropriate section for this question, because I guess it's kind of an interdisciplinary subject. My understanding of stereopsis (please, correct ...
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1answer
200 views

Why don't we have more cone cells (bigger fovea)?

Background Apart from being able to sense color, cone cells are able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods. ...
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2answers
114 views

Do people with colorblindness have less cones or no cones of a certain type?

https://en.wikipedia.org/wiki/Color_blindness#Red.E2.80.93green_color_blindness Protanopia (1% of males): Lacking the long-wavelength sensitive retinal cones, Deuteranopia (1% of males): ...
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1answer
54 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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1answer
2k 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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37 views

Sensitivity of eyes to flashing lights

My eyes are very sensitive to flashing lights - for example I'm always the first person to notice that a fluorescent tube is about to fail because I see it flickering when other people can't. When ...
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0answers
47 views

How can eyeglasses improve vision beyond 100%? [closed]

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?
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53 views

How well does the event-driven DVS sensor approximate the rods of the retina?

There is a neuromorphic vision sensor that is generating some interesting research these days that is called the Dynamic Vision Sensor. One of the claims of this sensor is good approximation of the ...
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383 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 ...