Biology Stack Exchange
Biology Stack Exchange

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.

The tag is used for questions directly relating to the , , and of the eyes.

For related questions on how the brain interprets electrical messages from the eyes, see the tag.

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Is there a reason why human eyesight and plants make use of the same wavelength of light?

The accepted range for the wavelengths of light that the human eye can detect is roughly between 400nm and 700nm. Is it a co-incidence that these wavelengths are identical to those in the Photosynthetically Active Radiation (PAR) range (the…
Rory M
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Are humans more adapted to "light mode" or "dark mode"?

I was discussing with a colleague about using dark-mode vs. light mode and remembered an article arguing that humans vision is more adapted to light-mode rather than dark-mode: I know that the trend “du jour” is to have a dark mode for pretty…
Alexei
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How long do your eyes need to adapt to darkness and reach full contrast?

I heard you should wait some time until your eyes adapt to darkness and are able to see smallest luminosity differences, otherwise you might overlook faint objects in the ocular. Are there any rules of thumb here? What about looking for 5 minutes on…
Hauser
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Why does looking at bright light trigger sneezing in some people?

Why does looking at bright light trigger sneezing in some people? Are there any recent studies that have found a cause for this Photic sneeze reflex? The Wikipedia article only references studies pertaining to the effect, stating that the cause is…
luvieere
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Why can't we see in low light if staring long enough?

For me it seems reasonable that if I kept my gaze on a fixed point in a room with low light, a progressively brighter and better picture would appear before my eyes, just like a camera can see in the dark if the shutter speed is really slow, e.g. 4…
filip
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Why do I see different hues of colors between each of my eyes?

Frequently, I see colors with a slightly different hue when looking through my eyes individually. The right eye is more red-tinted ('warmer' hued) and the left is typically more blue-tinted ('cooler' hued). However, sometimes I can't notice any…
theforestecologist
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When did vision evolve for the first time?

Today I wondered what the first organism to evolve vision would have been. I assume that it would have been kind of primitive and basic, but of course extremely innovative and eventually useful to a wide variety of beings. It also makes sense that…
magnetar
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How do birds deal with their eyes drying out at high speeds?

My eyes tear up when cycling at 15 mph, which is nothing compared to bird airspeeds. Do birds continuously produce lots of tears and blink a lot, or do the eyes self-moisturize from the inside without need of blinking, or are their eye surfaces just…
SuperElectric
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What portion of the electromagnetic spectrum do cats see?

I have seen numerous articles and various information about how cats and dogs see into the ultraviolet spectrum with interesting artistic renderings such as this: http://www.livescience.com/40459-what-do-cats-see.html But I have been unable to find…
ylluminate
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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 lying as he reeled off the whole number plate and…
Claire
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What is the difference between a circular and a cat's-eye (slit) pupil?

I've been to local zoo the other day and one lizard caught my attention: its pupils are circular, which, I thought, is not usual for reptiles. Turns out it is, but now I can't find any explanation on why some animals have one kind of pupil and…
Violet Giraffe
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Why do dog's eyes glow green on a photo?

Taking my current profile picture as a prominent example: This photo has been taken with flash. As I gather, this is the same effect that makes a human's eyes glow red on photos, namely the reflection of the flash at the choroid and then passing…
Vogel612
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Are there specific conditions that allow humans to see ultraviolet wavelengths

It is fairly common knowledge that the lens in its normal state absorbs ultraviolet (UV) radiation. An interesting notion has come up from time to time in my reading that suggests there are a small number of conditions that result in humans being…
user3795
15
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1 answer

Why do we go blind for a few seconds after switching off the light?

At night, when I switch off the lights, I always seem to go blind for a while. The room becomes pitch black and I am unable to see anything. After a while, however, my vision slowly recovers and I start to see things around me again. I always have…
علی آفاق
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How does this illusion work?

I found this image on Google+ If you shake your head you can see a portrait of a person. Can anyone explain how the image is constructed in the brain?
Green Noob
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