Questions tagged [eyes]

The discussion of the anatomy and evolution of eyes. Consider using the "vision" tag for questions regarding how the brain interprets information from the eyes.

36 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
4
votes
0answers
170 views

Eye color genetics

I am trying to find a model to link the phenotype eye color to its genotypes. I know that there exists a simple model from Davenport, which explains {brown,blue} eyes. Further, there is an extended ...
3
votes
0answers
84 views

(How) do horizontal pupils dialate?

I was looking at mongoose eyes in particular, but my understanding is: Circular (human-like) pupils simply get larger/smaller depending on light levels, no change in "shape" Vertical slit (cat-like) ...
3
votes
0answers
241 views

Is Near-infrared focused light safe for your eyes?

I found a new product, but I'm afraid it's not safe. Can you help me understand what the safety limits are when it comes to near-infrared light focused on your eyes is? I'm assuming the wavelength ...
3
votes
0answers
4k 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 ...
2
votes
0answers
72 views

The colors blue and golden (yellow-orange) and the human eye / brain

Many years ago I read a review in an article about why we love for example Lapis Lazuli so much. The article stated that there are two specific colors, yellow as golden (when it glows or shines) and a ...
2
votes
0answers
1k views

Does Rüppell's Griffon Vulture Have Greatest Vision Acuity? (Small Carrion Spotted at 10 km+?)

Synopsis: Some sources seem to imply the Rüppell's (griffon) vulture (Gyps rueppelli) can see objects at a distance in excess of 10 km -- roughly three times the ...
2
votes
0answers
57 views

What do I need to do to make a Reverse colorblind image?

As a 15 year suffering from moderate Protan colorblindness, I've wanted to find any advantages of colorblindness. I discovered there are Reverse colorblind tests, which only colorblind people are able ...
2
votes
0answers
61 views

Are there people who can change one of their eyes' depth of focus, while not changing the other eye's?

Are there people who can change one of their eyes' depth of focus, while not changing the other eye's depth of focus, without any surgical or other external mechanical intervention? Edit: let's ...
2
votes
0answers
84 views

Why do most fish move fins orthogonally with their axis of symmetry?

So recently I read the question why are most fishes vertical (in the sense of distribution of their body mass) and it got me thinking what is the reason behind the direction they move their fins. My ...
2
votes
0answers
582 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 ...
2
votes
0answers
29 views

Did the number of rods changed from ancient time?

Correct me if I am wrong, but I know that rods work under limited light conditions only. But now we are in a world that always have lights everywhere unlike ancient time when humans had to deal with ...
2
votes
0answers
835 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'...
2
votes
0answers
240 views

White/Gold vs Blue/Black dress

So I'm sure you've all seen the dress photo where people see the dress as either White and Gold or Blue and Black. It has essentially 'split' the internet because some people see the dress and they ...
2
votes
0answers
747 views

What does salt do to styes?

Styes formed in the eyes are cured by dabbing at them with lukewarm water(I saw this being done many a times as a home remedy.) At times, common salt is added to the water before dabbing. My mother ...
1
vote
0answers
25 views

What happens to eyelids when we feel sleepy?

Why is that whenever we feel sleepy, our eyelids start to feel heavier. It is not like we can any time close our eyes and will immediately fall asleep. But, when we feel sleepy our eyelids ...
1
vote
0answers
21 views

What is the average eye sight for humans? How bad is one's eyesight if you are1 or 2 SD below average?

What is the average eye sight for humans? How bad is one's eyesight if you are 1, 2 or 3 SD below average? I googled but it was hard to find good search terms.
1
vote
0answers
27 views

Would preserving your Eyes from Light keep them healhty?

I read about why eyesight diminishes with age. I am aware of the fact that there are different causes that can affect the quality of image received by our eyes and that being vague would not lead to a ...
1
vote
0answers
24 views

Does the ratio between M and L cone cells vary in one indiviual?

Wikipedia says: The ratio of M and L cones varies greatly among different people with regular vision (e.g. values of 75.8% L with 20.0% M versus 50.6% L with 44.2% M in two male subjects). This ...
1
vote
0answers
27 views

Does iris color effect the amount of light that reaches photosensitive ganglion cells?

Does eye color (of iris) have any effect on the amount of light reaching retina cells and hence effect melatonin production?
1
vote
0answers
1k views

What is the field of view of humans (not just fixed angle eyes)?

What is the human field of view also counting the maximum vertical and horizontal eye movement (rotation), with the head still. It is unclear from this question whether the answer relates to the ...
1
vote
0answers
77 views

Differences that are too small to see

Consider two identical pieces of paper. Scenario 1: On both something is drawn in black ink. If the difference between the areas covered in black ink is sufficiently small, I cannot see the ...
1
vote
0answers
105 views

Insects are attracted to light, what if the light is too bright?

Insects are known to approach light sources. I know that they use it as navigation tools, by maintaining a constant angle between their path and the light beam. However, if a light source is ...
1
vote
0answers
256 views

Why bipolar neurons in retina transfer information via graded potentials?

Why should bipolar cells prefer graded potentials to action potentials? My attempt: I know that graded potentials are better in processing information since stimulus is directly proportional to ...
1
vote
0answers
70 views

Do squids or octopus suffer from myopia(hyperopia)? Do other vertebrates get myopia(hyperopia)?

Both vertebrates and cephalopods evolved very sophisticated camera-type eyes, and both are capable of focus. But it also pose a risk of inability of focusing, such as myopia in human. So is myopia a ...
1
vote
0answers
2k views

Why does vision gradually becomes dimmer in bright setting?

I don't know if this is only happens to me, but if I am in a well lit room and I stare at one point or just look at one area without moving my eyes around my vision in that specific light setting ...
1
vote
0answers
322 views

Would a transparent iris serve its purpose?

The function of the iris is to regulate the aperture of the pupil. How does the iris obstruct light? Is it due to the pigment present in it? Or is it just due to the sheer presence of it? I am doing ...
1
vote
0answers
381 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 ...
1
vote
0answers
565 views

Would a VR headset exacerbate myopia or could it be used to retrain the eyes?

I've learned that there are two primary hypotheses to explain myopia: not enough use of distance vision or not enough sunlight If the distance between an eye and what it's focusing on is the primary ...
1
vote
0answers
184 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 ...
1
vote
0answers
119 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 ...
0
votes
0answers
59 views

Latest estimates for shortest and longest wavelengths of light visible by dogs?

Dogs (canis lupus familiaris) are dichromats, meaning that their eyes contain two types of cone, responding maximally to two different wavelengths of light, namely blue (429 nanometres) and yellowish ...
0
votes
0answers
11 views

Reason for acephalgic migraines

I suffer from acephalgic migraines, known commonly as ocular migraines. I’d like to know the reason why such migraines occur. Moreover, I’d be interested in knowing why do the following occur in the ...
0
votes
0answers
27 views

Does cataract condition cause red film when sun is shining?

Since two years ago I have a red film in my field of vision when the sunlight (or a white spot) is at the border (or even lightly behind) of the vision field, the red color is especially obvious at ...
0
votes
0answers
42 views

Difference in frame rates of normal and peripheral vision

I recently encountered an incident in my laboratory. It was evening and the sunlight entered the lab through a window with exhaust fans. So the ray kept flickering at fixed intervals. I noticed that ...
0
votes
0answers
4k views

Why do we see better on stretching our eyelids to the side?

I've often noticed that on stretching my eyes to the side I see a lot better. On searching, I read that this happens because the cornea reshapes itself (due to the ciliary muscles). But is that all, ...
0
votes
0answers
567 views

Why does a human's field of view narrow when moving faster?

A relative of mine is a driving instructor and he regularly likes to bring up that the field of view narrows noticeably when driving at higher speeds. Is this true, why is this so and does this apply ...