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

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7 views

How doctors can damage eye stye without damaging the eye ball? [migrated]

Yesterday I got Eye stye, i went to hospital, then doctor take needle he damaged the stye without touching the eye ball, we all know that stye usually form very near to eye ball, so how? even blood ...
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0answers
10 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 ...
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1answer
32 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 ...
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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 ...
4
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1answer
54 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
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1answer
60 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
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1answer
19 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 ...
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0answers
23 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 ...
4
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5answers
141 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 ...
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1answer
72 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
61 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
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1answer
30 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 ...
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1answer
51 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
52 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
37 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
80 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
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2answers
780 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
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1answer
69 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
122 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
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1answer
124 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
151 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.
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0answers
57 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 ...
12
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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
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1answer
815 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
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1answer
72 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
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1answer
410 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
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1answer
2k 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 ...
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1answer
117 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
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2answers
111 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
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1answer
86 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 ...
0
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0answers
24 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
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2answers
198 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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0answers
91 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
862 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
470 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
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2answers
189 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
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3answers
219 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 ...
6
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1answer
2k views

Is it biologically possible for an adult's eye color to change?

Can it be that the adult eye can change color? Specifically my question is about a unilateral color change, such that the color of one eye remains constant, while the other changes color over time. ...
1
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0answers
45 views

How to compare a camera and an eye

How could I compare what a normal eye can see to a camera lens? I just went through a very comprehensive article @ CambridgeInColor, but I'm still not really clear. When I take a picture with a SLR ...
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6answers
3k views

What is the use of eye banks, if eyeball transplants do not exist at present?

Corneas are donated and transplanted, but not the eyeball. I don't understand. What is the purpose of donating a cornea without an eyeball to a blind person?
1
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1answer
74 views

Does pupil size affect image focus in persons with no lens?

If an individual has no lens like Claude Monet (who had them removed). They should be able to still focus the images they see in a well light area if they shrink their pupils to a very small size ...
14
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1answer
238 views

Effect of pupil responses on the electroretinogram

The electroretinogram (ERG) is generally considered to reflect the retinal processing of a light stimulus, typically a photoreceptor response followed by secondary neuronal activity. I am wondering ...
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0answers
50 views

Nystagmus drug FDA approval?

Congenital Nystagmus is an eye focusing disorder. It happens in manuals. Wikipedia lists several treatments on its page. Are any of those FDA approved for human use of that disease. drugs found ...
3
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2answers
982 views

What is the scientific opinion on plus lens therapy?

Plus lens therapy is the theory that most myopia is environmentally triggered and that conventional corrective minus lenses increase nearsightedness over time. Thus the hypothesis that applying plus ...
7
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1answer
150 views

How does myopia develop, exactly?

Recently I was reading about myopia and I understood a few basic facts about it: Its initial cause is a constant spasm in the ciliary muscle. To do less work, the eyeball elongates a tiny bit. ...
3
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1answer
520 views

Do humans have the hyaloid canal, after all?

Most Google Images results for "eye anatomy" are pictures of eyes that don't have the hyaloid canal while some do (proof). Do humans have it, after all, or not? :)
2
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1answer
94 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 ...
19
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1answer
5k views

What do you see when your eyes are closed?

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...
6
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1answer
4k views

How the conjunctivitis virus spread just by seeing a person's eye who is infected

Conjunctivitis or 'pink eye'. I have a few questions on conjunctivitis. When I was suffering from conjunctivitis, my doctor advised me to wear sunglasses so that no one else gets infected. I ...
3
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1answer
349 views

Does human eye lens have a magnification of its own?

I have always wondered if the lens in our eyes have any sort of magnification by default. And if yes, if we're actually seeing everything around us bigger/smaller than what they actually are! Has any ...