46
votes
Accepted
Why can't we see in low light if staring long enough?
For simplicity's sake, let's really reduce this to something like photography.
A camera's aperture can stay open indefinitely, allowing the plate (or whatever is receiving and recording light) to "...
- 24.5k
30
votes
Accepted
Are humans more adapted to "light mode" or "dark mode"?
A question that requires quite a lot of guts to ask on this site :) Nonetheless, and risking sparking a debate, there are a few arguments that spring to (my!) mind that can support the notion that we ...
- 52.3k
21
votes
Accepted
Why do we go blind for a few seconds after switching off the light?
Short answer
The eyes need to adapt to the low lighting condition after you switch off the lights, a process called dark adaptation.
Background
The process behind the reduced visual function when ...
- 52.3k
19
votes
What are the floating translucent little objects called in the field of view?
I think you are talking about floaters (a.k.a. eye floaters or flying flies). You may want to have a look at this english.SE post in case you were not talking about floaters.
Floaters are deposits ...
- 67.9k
19
votes
Accepted
How deep under water can humans open their naked eyes without damaging them?
Crushing damage from pressure occurs due to pressure differences. Imagine you have a rigid container. If you have equal gas pressure inside and outside, the pressure acts on just the walls and the ...
- 42.4k
16
votes
Why can't we see in low light if staring long enough?
The simple answer is, that eye is not constructed such way.
The eye have much more "pixels" than "links" to the brain and sends in "preprocessed" image. Moreover the the eye is constantly moving and ...
- 261
16
votes
Why can't we see in low light if staring long enough?
The differences at the photoreceptor level have been addressed by others. The mechanical restrictions of the visual system were shortly hinted at by @gilhad et al., but deserve more attention in my ...
- 52.3k
13
votes
How deep under water can humans open their naked eyes without damaging them?
Goggles do not, cannot, protect eyes from pressure. The pressure on both sides of goggles should be nominally the same. In fact, divers tend to use a mask, which communicates with the nose, to be able ...
- 231
12
votes
Accepted
What is the function of the human eye white?
Short answer
The relative large surface area of the white sclera in humans has been linked to an enhanced ability to detect eye gaze.
Background
The white of the eye is caused by the sclera. Human ...
- 52.3k
12
votes
Why do I see different hues of colors between each of my eyes?
This is an interesting phenomenon which I have been aware of for several years, but I haven't yet come across any official description of it or explanation for it.
Nonetheless, the phenomenon is easy ...
- 883
12
votes
Why can't we see in low light if staring long enough?
There's probably a theoretical capacity to do so. The brain is amazingly good at signal processing, and could probably pull off such a summation. However, there is a limit. You have to hold very ...
- 1,364
11
votes
Accepted
Does your iris color have an effect on your vision?
Firstly, note that "eye color" is actually iris color.
The person with a lighter iris will have more straylight compared to person with brown iris:
The graph represents Intraocular straylight of ...
- 5,700
10
votes
Accepted
What is the rest state for eyelids - Open or Closed?
This depends to some extent on how you define "resting state" (it matters).
Innervation of the eye occurs in the brainstem and upper spinal column, so is, like most brainstem functions, on autopilot ...
- 24.5k
10
votes
Are humans more adapted to "light mode" or "dark mode"?
From experiments it seems you should better use dark mode if you want to prevent myopia:
Using optical coherence tomography (OCT) in young human subjects, we
found that the choroid, the heavily ...
- 201
9
votes
Do insects with compound eyes have depth perception?
Short Answer:
Yes.
Nityananda et al. (2018) confirmed a novel form of stereo vision by putting tiny colored glasses on praying mantises.
(Newcastle University, England) [source]
Long Answer
...
- 29.6k
9
votes
Accepted
Can a color-blind person see color with filter glasses?
Short answer
Optical filters can optimize color contrast, but never restore color blindness. Filters remove colors, they can never add something. However, glasses like this can prove helpful for ...
- 52.3k
9
votes
Accepted
Can "red" cone cells actually see much red light?
This is a good question. The first thing to note is that human colour vision is very complex and still poorly understood. If you visit the wikipedia page on RGB, you will find that this correctly ...
- 827
9
votes
Accepted
How do our eyes detect light at different frequencies?
Short answer
Action potentials generated to different colors are indeed similar throughout the nervous system and do not encode color as such. Instead, the different color- sensitive cells in the ...
- 52.3k
9
votes
If one of eyes is blind, can that eye still feel pain?
Blindness can be due to a damage of the lens, retina, optic nerve or the visual area at the occipital lobe of the brain, for example.
Sensitivity of the eye cornea is enabled by a different nerve - ...
- 8,049
9
votes
How deep under water can humans open their naked eyes without damaging them?
Currently the record for the deepest dive wearing scuba equipment is 332.35m. The descent took only 15 minutes while the ascent lasted 13 hours 35 minutes.
Liquids do not compress, so the sinuses, ...
- 10.3k
8
votes
Accepted
Can the retina emit light?
Please allow me to start by saying I know nothing about LEDs, so my answer isn't going to address your analogy. I'm also going to keep it more simple.
Can the retina emit light?
Yes. The retina is ...
- 24.5k
8
votes
Accepted
Why can myopic eyes focus on nearby objects, but not on distant ones?
There are four common refractive errors, namely nearsightedness (myopia), farsightedness (hyperopia), astigmatism (Fig. 1) and presbyopia.
Fig. 1. Refractive errors. source: Excimer Ophthalmologic ...
- 52.3k
8
votes
Accepted
Why can't we half-close our eyes?
The motion of the eyelid is driven by the levator palpebrae superioris, i.e. elevating muscle of upper eyelid, and it can be positioned to the intermediate, half-closed positions. At least I can do it....
- 204
8
votes
Accepted
How are colors outside the standard RGB color scheme perceived?
This question is both biology and physics I think (I guess it's biophysics! :) so I feel it's worth answering here.
First, we must recognize the difference between wavelength, which is just a ...
- 5,665
8
votes
Accepted
Can frogs see clearly under and above water?
Short answer
Frogs are nearsighted on land and farsighted under water.
Background
Frogs are reported to be nearsighted on land, but farsighted underwater (source: Chegg Study). Nearsightedness (...
- 52.3k
8
votes
Cerebral activity during exposure to non - visible light
Vision is based on a protein interaction with a molecule called retinal from vitamin A.
Wavelengths of light in the visual range cause a photoisomerization of retinal (a cis- to trans- change), which ...
- 42.4k
8
votes
Do animals with their eyes ~180 degrees apart have depth perception?
Worth noting, even you can perceive depth with one eye closed if you slide your head left and right. It's the same reason we can have 3d gifs that just rely on sliding the camera. Look up stereoscopic ...
- 81
8
votes
Accepted
Comparion between machine vision & human vision
This is a potentially very very broad question, but I'll try to provide a simple answer that addresses the biggest misconceptions.
First of all, animal vision (and brains more generally) is massively ...
- 42.4k
7
votes
Accepted
Why do snakes not have eyelids?
Snakes have no eyelids. Each eye is covered with a single, transparent scale. These eye scales protect the eyes from mechanical damage, and prevent the eyes from drying out, just as an eye lid would ...
- 52.3k
Only top scored, non community-wiki answers of a minimum length are eligible