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I'm designing an intelligent alien creature that lives in the jungles of a tidally locked planet, a little bit more massive than Earth, and which orbits a red dwarf. One of the things I designed about my creature is that they have three pairs of light green, (seemingly) pupiless, elongated eyes. For reference, here's an early sketch of what I imagine them to look like:

My 6-eyed alien head sketch

Now my question is, are eyes like these biologically possible? I thought about giving them compound eyes since many insects have strange shaped eyeballs, but my creatures are large land-based predators, so compound eyes might not be ideal for analyzing the environment. Apart from that, despite their insectoid appearance they're actually vertebrates and I'm not even sure if a vertebrate could evolve with compound eyes (Note: I'm not 100% certain with my decision of making them vertebrates or not yet, please tell me which do you think works best). As for the lack of pupils, I imagined something like a protective covering over the eyes like snakes have that just makes it seem like they lack pupils from an outside perspective, but I'm not sure if that would block their vision and how they would see the world. To sum it up, are eyes like these possible to evolve naturally, and if so why?

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    $\begingroup$ Just take a look at some modern crab eyes. The shape is plausible and the no pupils could be explained by the light. The eye shape could also be shaped by vertical eyelids. $\endgroup$ May 24 at 15:31
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    $\begingroup$ Do these eyes move inside of a socket? If so, almost certainly have to be roughly spherical. If not (the creature turns its head), pretty much anything works. Has more to do with the lens, depth of the eye itself, and so forth. And with (evolutionarily) primitive eyes, even those things are rather flexible. $\endgroup$
    – John O
    May 24 at 16:06
  • $\begingroup$ Here is a picture of a pretty human with large green pupilless eyes. (Link goes to an Amazon page selling women's sunglasses.) What fashionable prosthetic corneas can do, natural corneas can do too. $\endgroup$
    – AlexP
    May 24 at 16:54

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Sure, why not ? but see your eye lens and cornea have a round shape..

An eyeball contains fluid, so its "natural" shape will be round. The eyeball cavity in humans is quite large, so our eyeballs are sphere-shaped. However, when the cavity has a certain shape, the eyeball will adjust to that shape.

There will be no optical issues, as long as you take into account..

Eye lens

Like humans and other mammals, lizards change the shape of their lens to focus on nearby or distant objects. Snakes, on the other hand, move their lens forward or backward, which is similar to have cameras focus.

When designing the eye, see that the eye lens is disk-shaped and the retina behind that lens need to be dome-shaped, for best visual acuity.

The lens is the spheroid in the middle, this is a typical reptile eye shape, as you see the eyeball is not spheric,

enter image description here

Cornea

Your creature is reptile-like, so it will need a cornea up front. As the cornea is also a lens, the same optical rule counts for that part, it should be dome-shaped rather than elongated. The cornea needs not cover the eye. See you have a small, circular opening somewhere up front. If you can't give it a dome shape anywhere, make the cornea thin and flexible, so it approaches zero power. But that solution won't give it 20-20 vision !

Iris

The Iris is actually a muscle that decides aperture: the amount of light entering the eye. Especially important when your creature needs to adjust to day and night light. Its shape needs not to be round:

enter image description here

For your creature, a horizontal rather than vertical iris opening may be practical.

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Your creature has 2 eyes. Its eyelid is in the middle.

Depicted - your creature with eyes partway open as you have drawn, then completely open and almost closed.

eyes

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