Eye Retina Intromission Alternatives

[Michael McMahon]

Were the retina at the back of our eye like a concave mirror then is it possible the image would be reflected back out the converging lens (under the iris)? 

So the inverted image above is already formed in front of the retina (B’) and might essentially be re-inverted upright(B):

https://www.teachoo.com/10826/3118/Concave-Mirror---Ray-diagram/category/Concepts/

Then the image might be re-magnified on attempting to exit back out the converging lens under our pupil to potentially create a virtual image in the eye to simulate the reality we see:

https://www.teachoo.com/10838/3118/Convex-Lens---Ray-diagram/category/Concepts/#google_vignette

Cornea face reflection:

That way any appearance of eye beams from the eye would be passively reflected rather than actively emitted. However I don’t know the exact focal lengths of a potential retinal mirror to fully work out any resultant image.

An alternative theory might be to view the mind as being like a hidden periscope in the brain such that we’re desensitised to having an upside-down vision. Then the retina might function like a concave lens to minimise the image even further in order to reduce contrast with an upside-down version of the image:

“A researcher wearing goggles that inverted everything stumbled about wildly at first, but soon enough he was able to ride a bicycle.”

https://amp.theguardian.com/education/2012/nov/12/improbable-research-seeing-upside-down

 

Edited April 23 by Michael McMahon

[John Cuthber]

Reflection from the retina is what causes red eye in flash pictures.
https://en.wikipedia.org/wiki/Red-eye_effect

And you really need to look up what "intromission" means.

[exchemist]

36 minutes ago, John Cuthber said:

Reflection from the retina is what causes red eye in flash pictures.
https://en.wikipedia.org/wiki/Red-eye_effect

And you really need to look up what "intromission" means.

There is apparently a meaning relating to an Ancient Greek theory of sight, in addition to the more, er, Sid James sense of the word....... 

[Michael McMahon]

One way to view the retina as a periscopic concave lens is to view the image as a virtual image going backwards rather than forwards seeing as the concave retina is larger and might be more powerful than the pupil’s convex lens. 

https://mammothmemory.net/physics/lenses/concave-lenses/concave-lens--object-at-different-distances-from-the-lens.html

Then the incoming inverted image from the pupil’s convex lens would deflect off the hypothetical concave lens of the retina in a way that remained inverted in the vitreous humour as shown in the image above. However the deflected image from the retina might be re-inverted upright as a double negative after exiting the pupil’s converging lens for the second time although this time landing outside the eye in front of the head. 

This might happen for distant objects in human vision depending on the accommodation of the lens and ciliary muscles. The way some tarantulas can be way creepier than others like the less creepy jumping spider below might relate to their mysterious eyes. The lenses on such tarantulas are so small that whatever the creature sees might be demagnified due to the tiny focal lengths where objects in their vision would be beyond the focal point. 

[Michael McMahon]

Judging by the jumping spider one way to think of a tarantula being less creepy might be to try and focus on either the head or the eyes separately rather than simultaneously in order to avoid multitasking the reflection of the eyes with the slight neurological complexity of their brain. Viewing their retina as a concave lens might imply that the tarantula is mostly neurological whereas viewing their retina as a concave mirror might make the creature appear more transparent and photonic. The eyes are often hidden in smaller spiders such that it’s easier to view the creatures as neurological without the need to view their retina as a lens where the retina might be as small as a concave mirror. In other words if you’re afraid then you could dilute the creature as being deterministic and neurological or as being thoughtless and visual. The way the jumping spider’s eyes are black might imply that their vision is tinted darker or black. 

Edited April 24 by Michael McMahon

[KJW]

I find it quite bizarre that some people regard it as significant that the image on a retina is upside down. It's like wondering how the images on a DVD are turned upright on a TV screen.

 

[Michael McMahon]

One reason many Australians and Brazilians might not be too afraid of large spiders and snakes might be that the head-size of tarantulas are comparable to a snake head even though a snake would have a much longer body. This might help to counteract the mysteriousness of their minimal psyche even though I’m not too sure if most arachnophobes also have a fear of snakes. I was slightly creeped out looking at online photos of tarantulas yesterday only to have a dream of carrying a snake box last night as if to neutralise the initial fear of tarantula images. 

[swansont]

16 minutes ago, Michael McMahon said:

One reason many Australians and Brazilians might not be too afraid of large spiders and snakes might be that the head-size of tarantulas are comparable to a snake head even though a snake would have a much longer body. This might help to counteract the mysteriousness of their minimal psyche even though I’m not too sure if most arachnophobes also have a fear of snakes. I was slightly creeped out looking at online photos of tarantulas yesterday only to have a dream of carrying a snake box last night as if to neutralise the initial fear of tarantula images. 

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Moderator Note

What does this have to do with optics? Please stay on topic, whatever that is

 

[Michael McMahon]

1 hour ago, swansont said:

!

Moderator Note

What does this have to do with optics? Please stay on topic, whatever that is

 

I understand and will try to avoid snake and spider analogies. For my previous point in terms of optics I was merely alluding to how an 8-eyed tarantula with 6 more eyes or 3 more pairs of eyes than a snake doesn’t directly have an extra 3 times more consciousness than a snake. 

Edited April 25 by Michael McMahon

[Michael McMahon]

Apologies for one last spider analogy but I think it bears directly on optics. One way to think of a tarantula’s eyes is as a mirror maze. One way a tarantula can inflict karma is that the creature has good short-sighted vision as if each peripheral eye served as reading glasses for the central eyes such that to objectify the creature can accidentally risk objectifying part of our own vision. One ironic reason the huntsman spider below felt creepier than the jumping spider in post 4 is that the jumping spider had larger peripheral eyes to deflect from their central vision whereas the huntsman spider has relatively smaller peripheral eyes as if to emphasise binocular vision like a human. On first impression the lower peripheral eyes on the huntsman spider were almost like an eyebrow frown to give an angry expression which is a creepy anthropomorphism. So if the retina of the eye in a huntsman spider served as a concave mirror to reflect the image back onto the rear-eye side of the convex lens only to magnify the image back onto the retina then each eye would recursively reflect the image to other eyes like a mirror maze or infinity mirror. So even if the tarantula had good short-length vision then that doesn’t mean the tarantula is conscious of all of their vision because the peripheral eyes would make their vision too difficult for the tarantula’s small brain to understand. I’m not necessarily trying to promote a fear of tarantulas but those who don’t fear them might not actually know why others fear them. 

My first instinct was to focus on the central two eyes and lower peripheral eyes but glancing at the top two eyes on the side of the head can help reduce anxiety as if the creature almost had eyes on the back of its head as a source of bewilderment for the spider. That way the way spider’s vision is made more unconscious like how the faster speed of quadrupedal wolves doesn’t make them more conscious than a human. 

Edited April 25 by Michael McMahon

[swansont]

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Moderator Note

You posted this in classical physics, about optics. Optics is what needs to be discussed. Not karma or creepiness or arachnophobia (which you had a thread on, and it was closed) or any unsubstantiated musing on any topic.

 

 

[Michael McMahon]

“Alternating current is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction.”

One way to view the neurons in the brain is as alternating current rather than direct current such that our mind would swing between both halves of the brain like a pendulum. For example some synapses in the brain are multi-polar with multiple dendrites. So the way we can close one eye and lose some of our conscious awareness of blackness on that eye while looking out the other eye might feel as if our mind’s eye mind was in one brain location with both eyes swapping like each eye were an alternating scope. The partial blackness on the winking eye can help your depth perception where if you rotate your head towards the winking side and look out the same corner then the blackness of phosphenes above your nose will stand out a centimetre forward. An irony of viewing out with only one eye is that you might think your locus of consciousness was behind the middle of that eye instead of behind your nose as if your visual cortex swapped to the same brain hemisphere as the open eye. With monocular creatures like horses it’s possible to think if the creature had no brain then shining light through one eye might go straight out the other eye as if light had been teleported between both eyes. That way parallax could be helped by tiny time differences between both eyes as if the brain could virtually wink between both eyes were we to look at an angle towards a light bulb. 

Our mind is somehow levitating between both sides of the visual cortex with the nerves from the left and right sides of each individual eye diverging in the optic tract towards the visual cortex. 

I was musing beside a horse a few days ago! If both of our human eyes acted like projectors towards the back of our skull then they might naturally superimpose into one image. 

 

Edited April 28 by Michael McMahon

[swansont]

10 hours ago, Michael McMahon said:

“Alternating current is an electric current that periodically reverses direction and changes its magnitude continuously with time, in contrast to direct current (DC), which flows only in one direction.”

One way to view the neurons in the brain is as alternating current rather than direct current such that our mind would swing between both halves of the brain like a pendulum. For example some synapses in the brain are multi-polar with multiple dendrites. So the way we can close one eye and lose some of our conscious awareness of blackness on that eye while looking out the other eye might feel as if our mind’s eye mind was in one brain location with both eyes swapping like each eye were an alternating scope. The partial blackness on the winking eye can help your depth perception where if you rotate your head towards the winking side and look out the same corner then the blackness of phosphenes above your nose will stand out a centimetre forward. An irony of viewing out with only one eye is that you might think your locus of consciousness was behind the middle of that eye instead of behind your nose as if your visual cortex swapped to the same brain hemisphere as the open eye. With monocular creatures like horses it’s possible to think if the creature had no brain then shining light through one eye might go straight out the other eye as if light had been teleported between both eyes. That way parallax could be helped by tiny time differences between both eyes as if the brain could virtually wink between both eyes were we to look at an angle towards a light bulb. 

Our mind is somehow levitating between both sides of the visual cortex with the nerves from the left and right sides of each individual eye diverging in the optic tract towards the visual cortex. 

I was musing beside a horse a few days ago! If both of our human eyes acted like projectors towards the back of our skull then they might naturally superimpose into one image. 

 

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Moderator Note

No optics, and chock full of unsubstantiated musings. The opposite of what I said.

 

Don’t bring this up again.