How could be a relatively "universal" eye?

Question

In searching of a universal eye, I meant a photoreceptive organ which can have all/most of the best capacities of the known eyes.

So, each type of eye or photoreceptive organ has a different function or specialization, for example the human eyes are one of the best for combining multiple characteristics like resolution and color vision, enough long distances vision but not as an eagle, meanwhile in the other hand, mantis shrimp can detect different wavelenghts outside the human color vision like infrared and ultraviolet. Eagles have an excellent long distance vision, and other birds like owls have the best night vision with highest concentration of rods and cones. Other cases are different eye shapes like the chameleons which developed multidirectional eyes and passing a different shape to the pupils confers different characteristics, predators have rounded pupils for focalizing light, while preys have squared pupils for a near to 360° vision.

And there are more examples that I don't probably know, so I was searching for a "perfect predator" (concept can change), and I found an idea from this guy:

Kuwonics can change shape of their pupils! These properties make them the greatest watchers in the galaxy, they can have night vision by magnifying and changing the shape of their pupils on a dark night, or they can continue to see underwater, or they can concentrate all their cells in the same place, turning themselves into living binoculars.

This concept correctly fits what I'm looking for, but I don't know if it's possible, so probably I can retake the concept and change some things that could "upgrade" it for my objectives, but still existing problems about a "shape changer pupil", things that I don't how solve or how could work like the configuration of a tapetum lucidum, cones and rods and nervous arrays.

But also you don't need to be abide to this concept, you can answer what set of characteristics you can consider a "perfect eye", because should be emphasized that many characteristics for an eye could be solved for other organs, for example birds can't roll their flat eyes but some have a great neck rotation, snakes have thermal detectors and in some occasions, echolocation could be a better choice than excessive good light capture for nocturnal vision.

Happens that in one of my currents projects I want to use this eye for a plausible "perfect organism" (current concept could change to perfect human or perfect apex predator), for which later I will present the set of characteristics that I have selected in a different post, because I believed that this eye deserved its own questioning. Also an explanation of how this could evolve is not necessary or obligatory. That could be fine but it's not necessary, this can even be explained in terms of genetic engineering.

First of all, Thanks.

Answer 1

It certainly seems plausible:

• Regenerating eyes or parts thereof is not unknown in the animal kingdom, having been observed in rabbits, salamanders, zebrafish, dogs, mice, frogs, etc, however this normally takes weeks or months, even years. But there is a species of spider, deinopidae, which regrows its incredibly sensitive membranes each night.

• The mechanism you've described suggests a stem cell-like function to the host cell, instructing the 'smaller' free-floating cells to generate specific ocular structures.

So the potential barriers to this are speed—getting destruction and regeneration down to a few minutes at most—and instructing the host/stem cell, both of which are reasonably handwaved away by invoking an alien metabolism and evolution of specialized optic nerve–brain synaptic connections.

Answer 2

Some things to consider:

• Shape Changing Pupils: this is plausible, and in fact we do this all the time! The pupil is simply the open space or aperture left open to light transmission by the veiling property of the iris. The iris a muscular diaphragm that controls the pupil's size by relaxing or contracting. Changing the shape of the iris, within sensible (realistic) limits, would be a matter of organising the muscles and their nerves differently with respect to how it's done in humans. All we can do is (unconsciously) make the aperture larger (low light) or smaller (bright light). For purposes of your beings, their muscles are arranged in such a way as to allow different shapes to me formed. You could even have tiny "micro irises", if you wish.
• Pupils as Magnifiers: this is not plausible. Simply put, magnification is not a function of pupil size or shape in real world eyes. Magnification is a function of the lens, which is the clear structure that resides in the anterior chamber, just behind the iris.
• The Perfect is the Enemy of the Good: this is more a matter of design principle. The eye is always a product of trade offs, as you yourself note (this kind of eye has excellent distance vision, but can't see close up well; that eye has great low light vision, but can't see colours well). These trade offs arise mostly due to the circumstances of the creature whose eyes they are. A diurnal creature will have little need for low light vision; but will have greater need to distinguish tiny movements that could signal predator activity. You can certainly tick all the "perfect" boxes for your beings' eyes; but your design trade-off will be diminishing plausibility.

Answer 3

• as @elemtilas mentions the pupil shape and size. This will be connected to the amount of light gathered, but the slit pupil for predators give improved depth of field and the ability to judge distances while horizontal pupils are more useful to detect predators giving a wide field of view but along the plane.
• the mantis shrimp you mention is a wonderful example of having photoreceptors with very narrow wavelength response and covering a very wide spectral range from the near UV to the near IR, but interestingly the mantis shrimp eye is also sensitive to different types of polarization. So in addition to just the color of the light you may want to consider polarization. Lots of things in nature have what is called form birefringence that can alter polarization and the amount of reflected light off of surfaces can be polarization dependent.
• the way the way the "pixels" of the eye are connected and the preprocessing that can occur before sent to the brain for interpretation can also be interesting. For example, only firing the neuron if there is a change makes an movement detection more sensitive. A lot of very simple image signal processing algorithms effectively only sum or take the difference of the surrounding pixels. Things like this can highlight the outlines of images which is again useful for seeing moving objects.
• the sharpness of the image is dependent on the aberrations and the shape of the lens, the size of the aperture also limits resolution bigger being better resolution, but a bigger pupil also increases the amount of light that is passing further from the center of the lens and increases the aberrations. Making a lens adaptable to correct for aberrations could be useful. This could be done by specialize muscles pulling or bending the lens of they eye.
• organically controlling the magnification is more problematic there is only so much room in the eye and typically more than one lens would be considered and would be separated by a distance. However, ike the digital zoom in a camera once you have an image on a retina, you if had the ability control what region of pixels would go to the brain you could effectively have some form of magnification.
• similarly if your retina had the ability to integrate the number of photons over time, you might be able to significantly improve the ability to see in dim light, but at a slower time response. Maybe meditate and stare at something in the dark...

Answer 4

I'm afraid that rather than not being possible, it's simply not advantageous for something you plan to be the perfect predator to need to reconstruct its eyes depending on what it wants to do. Let's assume it's hunting prey with sight alone: it will likely want to see ultraviolet so that it can see traces of urine and better tell a camouflaged prey from its hiding place, and infrared in case it's prey is warm-blooded to further aid in tracking it and telling it apart from the vegetation it camouflages against. It was successful and hunted it, now it wishes to hunt underwater, so it must deconstruct its eyes and rebuild them into something more adapted to underwater hunting, except it's previous eye already had traits also used to hunt underwater, such as a large pupil and high number of photoreceptors, so it's waiting both an unnecessary amount of energy and an eye structure that was already mostly fitting for the task, with the biggest matter being its ability to operate in water and the percentage of cones and rods in it.

You see, looking at a creature's eyes, how they work and how they're positioned can tell you a a few things about it, sometimes even hinting how it lives (example: creatures with forward facing eyes usually need good depth perception, and is a trait seen both in many predators as well as in some arboreal creatures which need to be able to calculate the distance between 2 branches). Going a bit away from earth biology as we know it, the potential eyes of your "perfect predator" and it's very name seems to tell me one thing: your creature is most likely a carnivorous shape-shifter, which can and will change its overall shape according to the environment it's in and what it's hunting, which is the only way I can see it being capable of giving any predator which is already highly adapted to their niche a run for their money: mimicking their millions of years worth of adaptations on the fly so that it can have a chance to outcompete them to begin with. However since it's a science-based question I'll stop approaching this scenario, as no creature over 50 cm long (because I'm not sure about certain smaller creatures) on earth, as far as I know, can actually change its entire structure on the fly and to such a degree like this hypothetical hunting machine does, with the closest to a living example being the mimic octopus (which can mimic the appearance and behavior of several creatures in its habitat on top of its camouflage abilities, but that's about the limit of how much it can "become" the creatures they mimic).

Now, putting aside how the rest of its body works and simply assuming its vision is the most important factor on whether it can hunt something or not, it still doesn't look practical, simply because we're talking earth biology here. Even if we're talking about a bioengineered creature, I still think a single pair of eyes which can change :

1- while several eyes are much more costly to maintain than 1,they also ensure you're always ready to make up for said cost. If you need to hunt a creature, whether it's in land, in water, in bright or dark conditions, it will always be ready to use the eyes it needs. Meanwhile if the single pair creature needs to leave the water to hunt on land for some reason, it will need to first adapt its eyes, which takes a good amount of time and also a good amount of energy (remember it's basically destroying the previous eye structure and forming a new one in every change), and while I can't tell exactly how costly it is or how long it'd take due to not remembering any good real life comparisons, it sounds superficially like a reasonable disadvantage for not too big of a difference in energy efficiency, especially if it needs to change its eyes often enough to have developed this ability to begin with, assuming a natural evolution approach. The only advantage I'd see here is if it was bioengineered, and simply had it but didn't use it too much that it became too costly, at which point it might have been better to just make different versions of the creature adapted to different conditions.

2- animals often don't only use their eyes to see the world. For this let me use one of my favorite animals: the vampire bat. It is considered to have good vision, especially at night, but it also has great hearing, which is good enough to both let it echolocate its way through the darkness as well as to find animals it has fed on previously simply by the prey's breathing. Once it finds the prey, it will use infrared sensors on its nose to locate blood vessels closer to the skin surface, which it will cut open and use to drink the animal's blood. In this simple example he have a naturally occurring creature using 3 different sensing organs/structures to hunt. Truth is: few creatures will rely solely on a single sense to find food or to live its life. You want eyes which can see ultraviolet and infrared? Why not leave ultraviolet to the eyes while letting the infrared to a pair of pit organs? Do you really need to have good night vision or can you make up for the lack of it with echolocation? If you can't even see your prey, why not listen for or sniff for it? Simply handling every aspect of navigation and hunting to the eyes alone sounds like a poor choice of design, and is not something we actually see often in nature, which helps demonstrate how it's not always a good idea. Even some owls, usually known for their great vision, will also rely on their ability to hear in 3 dimensions to hunt prey hiding under the snow.

Now: whether it can actually happen: I don't think a pair of eyes which can just digest and reform themselves according to the environment the creature's in are an efficient alternative, nor do I think it can occur considering earth biology alone. The closest thing from this alternative which could actually work in reality, as far as I see (ha? Haaaaa?), is to have a creature which, via a weird evolutionary history (which likely evolved an ancestor which had to live and navigate between drastically different environments) or simply via bioengineering, ended up having multiple pairs of eyes, with each pair adapted to a different environment (in your creature's case, around 3 to 4 pairs I'd say).

In regards of my vision of a perfect eye: ideally one much like the one you wanted, capable of changing according with the environment the animal's in, but on a more realistic perspective, the perfect eye is an eye which attends the needs of the creature, and which works in conjunction with other senses to form a full picture.