Questions about the biological function and structure of the human eye.

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2
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0answers
14 views

Do primate RGCs have overlapping receptive fields?

According to this link, http://hubel.med.harvard.edu/book/b10.htm retinal ganglion cells (RGCs) receive input from overlapping receptive fields (RFs). This is also an idea used in convolutional ...
7
votes
1answer
59 views

Why do we blink instead of winking each eye independently?

Question Why do we blink both eyes at the same time rather than winking each eye as needed? Why would winking independently be better? The benefit would be a minor improvement whereby a person ...
2
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0answers
39 views

Why are eye defects so common? [duplicate]

The title says it all, what makes eye defects so common in the world? Whereas defects of any other body part is quite uncommon, I searched online and one of the articles said that 6 out of 10 people ...
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0answers
15 views

Can one eye affect the other eye's low-light adaption?

This previous question addresses how long eyes need to adapt to darkness and reach full contrast. My question is how does one eye affect the "transition" and/or efficacy of this "night vision" of the ...
18
votes
1answer
855 views

Why can't I read everything in my field of view?

When I look at a piece of text, I can see all the text on the paper, no matter where I look, because my field of view covers it all. However, if I stare at a specific word, I cannot read the text a ...
6
votes
2answers
279 views

Why can't our eyes smoothly transition from side to side without focusing on a moving object?

Why are we not able to slowly and smoothly look from side to side, or up and down in a single and smooth transition, given that we are able to do this if our eyes are focused on a moving object?
8
votes
3answers
117 views

How many mega pixels does the eye have?

What is the number of mega pixels available in the human eye? It seems that newer camera models continuously keep increasing their pixel count. However, they never seem to be capable of reproducing ...
1
vote
1answer
58 views

When you blow through your nose while holding it closed to “depop” you ears, why do you sometimes feel it in your eyes?

After your ears have "popped", for example on a flight, I heard you are supposed to hold your nostrils closed and blow through your nose to readjust the pressure to the normal level. Why do you ...
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0answers
13 views

How do macromolecules (large drugs) in the eye reach the bloodstream and what are the relative significances of these pathways?

I am considering the elimination pathways for antibodies (50-150 kDa) from the vitreous humour to the blood stream. My overarching question is what is the most significant route such antibodies could ...
1
vote
1answer
75 views

What causes the bright flash of light when poking my eye?

Recently, I poked myself in between my eye and eye socket, right below my eyebrow, and sometimes I would get this flash of light. Others have tried this too, and they also had a flash of light. I am ...
4
votes
1answer
68 views

Is it easy to test human Flicker Fusion Threshold?

How would you go about testing human flicker fusion threshold? Is the testable rate consistent in humans over time or volatile?
5
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1answer
95 views

Where in the world does blue eyed whites originate from?

I know that there were no blue eyed people until ~6000 years ago due to a mutation and all blue eyed people have a single common anchestor. But where in the world does it originate? I assume it ...
1
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1answer
19 views

Corneal transplant and HLA matching

Is HLA matching/ blood grouping required for corneal transplants ? I think,it shouldn't be, because cornea is avascular. I tried searching on the net but most of the references are old and ...
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0answers
24 views

How quickly can lasers of various wavelengths and powers impair human vision or cause pain in the eyes?

There is a discussion on HackerNews about how self-driving cars might be susceptible to confusion attacks using a cheap laser pointer and a RaspberryPi. Some people argue that human drivers, too, are ...
0
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0answers
15 views

What is the permeability of proteins across the hyaloid membrane of vitreous to retina?

Does anyone know of any experimental work to test the permeability of the hyaloid membrane between the vitreous humour of the eye to the retina to proteins? Currently the largest molecule I can find ...
0
votes
1answer
72 views

What is the surface area of the vitreous humour in contact with aqueous humour?

This is a question regarding the anatomy of the human eye, however for my purposes medium sized mammals should do. I am interested in estimating the surface area of the hyaloid membrane of the ...
0
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0answers
7 views

How do drugs (or other molecules) move between the vitreous humour and aqueous humour of the eye? [duplicate]

My question is regarding the biological nature of the separation between the vitreous humour and aqueous humour of the human (or mammal) eye. What connects the two in terms of the passive transport of ...
3
votes
1answer
125 views

How are the vitreous humour and aqueous humour of the eye, connected?

My question is regarding the biological nature of the separation between the vitreous humour and aqueous humour of the human (or mammal) eye. What connects the two in terms of the passive transport of ...
4
votes
1answer
74 views

What is the fluid clearance rate inside the retina?

I'm attempting to model the chemical concentration between several compartments of the eye, including the retina. Does anyone have any idea what the rate of fluid removal is in the retina, or could ...
0
votes
1answer
25 views

What happens in lasik operation?

First of all,I am very bad at biology. So please bear if it sounds elementary. I heard about lasik operation for reshaping cornea. Assume the patient is suffering from myopia implying lens is ...
0
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0answers
28 views

Undistorting peripheral vision

I am interested in a procedure which can be applied to an image (or video) which is situated in my peripheral vision, and will result in an undistorted copy being presented to my brain. I do not know ...
5
votes
5answers
371 views

Why is human vision restricted to 400-700 nm?

Across the electromagnetic spectrum, 400-700 nm is a narrow spectrum of frequencies and focused in the region of short wavelengths. For example, radio waves cover a large range of frequencies ...
0
votes
1answer
158 views

Why does our eyes got wet when we feel emotional or whenever we are hurt? [duplicate]

I was thinking like whenever when we feel emotional or whenever we got hurt we got tears from our eyes but why is that happen ? Why our eyes got wet ?
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0answers
78 views

Why my right eye see warmer colors? [closed]

As the title says, my right eye see warmer color than the left one. I've seen a few people talking about that thanks to google, but I was unable to find a proper answer. So, what cause this strange ...
4
votes
1answer
35 views

Wearing sunglasses during a solar eclipse [closed]

Note: I had asked this on Physics, but it is off-topic there due to being about safety. On the BBC's guide to eclipse-watching, Dr Lucie Green says: Watching an eclipse with normal sunglasses ...
1
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1answer
76 views

Is it safe to look indirectly at the Sun?

I.e., is exposure of sunlight onto the peripheral vision less damaging than exposure onto the fovea?
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0answers
90 views

Why are there ghost images of objects just out of focus

I have observed an interesting phenomena with my vision lately. I just think I have never reflected over this before but it might always have been this way. I am nearsighted and have no problem with ...
2
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0answers
39 views

Infrared emitting diode eye safety

I'm thinking of creating my own laser tag system and am a bit concerned about the eye safety aspect. Most of the homebrew system I've seen use the TSAL 6100 ...
3
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2answers
126 views

Myopia as a microscopic superpower?

A few years back my Physics professor made a joke that his myopia (i.e., nearsightedness) gave him a "superpower" that allowed him to see close objects much more clearly than someone with typical ...
4
votes
2answers
2k 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 ...
2
votes
1answer
637 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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0answers
209 views

Reason for different color perception in left/right eyes?

What could be the reason for a difference in color perception between the two eyes of an adult individual without any known eye conditions? In particular, a difference in the perceived color ...
3
votes
1answer
252 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 ...
1
vote
1answer
432 views

Are the irises an exact match in a human's set of eyes?

Are the irises an exact match in a human's set of eyes? Assuming the eyes are healthy with 20/20 vision.
2
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0answers
87 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 ...
13
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3answers
3k views

Superhuman eyesight

My ten year old son was reading car number plates that were too fast, too far away and at the wrong angle for any of us to read or even believe that it was possible for him to read. We thought he was ...
7
votes
1answer
2k views

Why do human eyes glow red on a photo and dog's eyes green?

Previous Research I know that cameras sometimes come with an anti "red eye" functionality that involves two flashes, presumably the second flash coincides with the shutter opening. Question Why do ...
1
vote
1answer
87 views

Why do eyes water in response to particular emotions?

It is common for people to experience very moving situations (sad movies, etc) and have a physical reaction to it (such as crying). I am curious about how emotions can physically lead to the act of ...
5
votes
1answer
803 views

Why do we get 'bags under our eyes'?

Why do these circles form around the eyes if somebody is tired? And why does fatigue express itself around the eyes this way? Can I get eye bags very quickly in another way? ...
8
votes
1answer
4k views

What is the field of view for the human eyes?

I'd like to know how much a person can see regarding the angles. If it is a rectangle, I'd like to know it's height and width. But if is another shape, I'd like to know which kind of shape and the ...
0
votes
1answer
157 views

Why do humans have eyebrows? [closed]

Why do humans have eyebrows? It seems that it isn't necessary but only humans have them, correct? So what is the use of them for humans? I hear that they protect our eyes. However, isn't that what ...
2
votes
2answers
132 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?
5
votes
1answer
107 views

Is it dangerous to rub closed eyes?

Phosphene from rubbing the closed eyes where first described at least since Ancient Greece, but I caught myself thinking that I wouldn't want to try it out. So I wonder, how safe it is to actually rub ...
1
vote
0answers
26 views

Why after physical activity I see flickering concentric circles? [duplicate]

After prolonged hard physical exercise such as running uphill I sometimes experience rapidly vibrating black-and-white concentric circles for a few minutes, looking like a sinusoidal zone plate, small ...
4
votes
2answers
348 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 ...
1
vote
0answers
117 views

Eye strain using 3D screens

I don't know if this is a physics or a biology question but this might be better orientated around the element of how the human eye works in a 3D visual situation than physics. Given the rise of 3D ...
9
votes
1answer
4k views

What's the smallest size a human eye can see?

During a biology experiment at school, where we would look at waterweeds under a microscope, my teacher said something about that it's impossible for the human eye to see the cells without a ...
4
votes
1answer
1k views

Why are irises unique?

I heard that irises are different and unique for every person. According this link, probability of two irises having identical pattern is 1 in 10 to the 78th power. That's how iris scanners identify ...
5
votes
2answers
357 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 ...
5
votes
3answers
267 views

Why do human ears have a lower boundary for the lowest energy perceivable signal than eyes?

I am currently hearing a lecture about human machine interaction. The lecturer is not a biologist (neither am I, we are both computer scientists), but he makes some statements about biology which I ...