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

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is the red eye reduction lamp dangerous to an infants eyes? [on hold]

is the red eye reduction lamp dangerous to eyes? I have a friend who is concerned about us taking so many pictures of her 3 month old.
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0answers
15 views

Do blurry images cause eye strain? At what point is an image so blurry the eye stops trying to focus it?

I'm a user experience designer concerned about a new trend of blurring screens when showing a lightbox/dialog box over top (see below). From what I know, blurry images cause the brain to work hard ...
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1answer
125 views

How can alcohol cause blindness?

Strong alcoholic beverages (e.g. moonshine) are reported to have caused blindness amongst some people. How exactly can alcohol make someone go blind? Is that because different forms of "rubbing" ...
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0answers
31 views

How fast the human eye can [temporarily] change its color?

I know that human eye can change its color during lifetime because of disease or medication (similar question on Biology.SE). And I know that it may change depending on the lighting. But I saw ...
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1answer
68 views

Relaxing Eyes when using Virtual-Reality-Glasses?

Accommodation is the process by which the vertebrate eye changes optical power to maintain a clear image or focus on an object as its distance varies (eye focusing). For distant vision, the ciliary ...
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14 views

Does the change in eye color (melanin concentration) affect the iris pattern?

In cases of acquired heterochromia, is there a quantifiable change in the iris pattern; the clefts , furrows, etc. If yes, what changes are observed? And if no, are there any diseases or acquired ...
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0answers
17 views

Controlling the pursuit path of the human eye

The human eye scans images by panning focus along a certain path. Stork et al. (2002) revealed that there is a feedback process involved in moving ocular focus along a path that produces minimum ...
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1answer
102 views

Does our brain contain an innate function about closing only one eye?

I wasn't sure where to post this, but biology seemed fitting for me. Sorry if I'm wrong. I was wondering why, when we close both our eyes and look at light, it is clear we can see the light even ...
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0answers
42 views

The evolution of poor eyesight: is there weaker selection in modern humans? [duplicate]

Short question: Poor eyesight might have been a major impediment to survival and reproduction in early man (say, 100,000 years ago), but, with the advent of agriculture, major cultural changes, and ...
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1answer
61 views

Why eyes don't get heated while converging sunlight into retina?

It is a common observation that a magnifying glass when used to converge rays of sun to a fine point in paper, the paper burns due to intense heat. Why doesn't this happen in our eyes? Our eyes are ...
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0answers
25 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 ...
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1answer
183 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 ...
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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
72 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
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1answer
885 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 ...
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2answers
383 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?
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2answers
152 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 ...
2
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1answer
84 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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1answer
27 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 ...
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1answer
173 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 ...
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1answer
97 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?
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1answer
106 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 ...
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1answer
23 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
27 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 ...
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0answers
22 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
108 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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1answer
266 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 ...
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1answer
77 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 ...
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1answer
49 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
29 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 ...
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5answers
889 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
288 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
87 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
56 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
108 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
105 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 ...
3
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0answers
43 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 diode(http://www.vishay.com/docs/81009/...
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2answers
167 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 ...
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3answers
4k 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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1answer
1k 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
277 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
473 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
859 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
102 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 I'...
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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 ...
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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 ...
2
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1answer
96 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
1k 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? http://www....
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1answer
6k 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
193 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 ...