Fiber optic light pipes in the retina do much more than simple image transfer

A case in point are the Müller glia cells that span the thickness of the retina. These high refractive index cells spread an absorptive canopy across the retinal surface and then shepherd photons through a low-scattering cytoplasm to separate receivers, much like coins through a change sorting machine. A new paper in Nature Communications describes how these wavelength-dependent wave-guides can shuttle green-red light to cones while passing the blue-purples to adjacent rods. The idea that these Müller cells act as living fiber optic cables has been floated previously. It has even been convincingly demonstrated using a dual beam laser trap. In THIS case (THIS, like in Java programming meaning the paper just brought up) the authors couched this feat as mere image transfer, with the goal just being to bring light in with minimal distortion.


another failed prediction of evolutionery theory: “Having the photoreceptors at the back of the retina is not a design constraint, it is a design feature”. evolution predict A while ID predict B, and indeed we found B.

Except that was never a prediction of evolutionary theory :roll_eyes:


many evolutionery biologists claimed that this is evidence for poor design/common descent, since the retina seems to be in the wrong order (backward) in all verterbrates. one explanation was that this is because all vertebrates share a common ancestor, and therefore stuck with this flaw. ID on the other hand predict that this order has a good functional reason, and this is indeed what we find. this is a great example of why ID is a good science.

And I explained before this study why that wasn’t actually the what evolutionary science predicted. Turns out either way is consistent with evolution.

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No one claimed the inverted retina was evidence for common descent. Stop making up false stuff in your head.

Yes, some evolutionary biologists claimed the inverted nature of the retina was poor design, but it was never a prediction of evolutionary theory. I don’t know where you got that from.

Common descent explains why all vertebrates share a similar eye design, but it says nothing about whether that design is good or not. Similarly, common descent explains why you and your siblings (if you have any) share certain features with either your mum or dad, but it says nothing about whether those things you inherited are good or bad.

Evolutionary biologists also stated that vertebrate eyes are functional and worked pretty well before this study came out. Some just thought it was poorly designed and new evidence appears to disagree with that claim. Similarly, biochemists thought free radicals were solely bad byproducts of many metabolic reactions in the body, until they learned they played vital roles as well. That’s why we do science to unearth these facts.

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I just read the paper and am frustrated that we are discussing that press release. “Fiber optic light pipes”!?!? Good lord.

In fact the paper seems to be about the opposite of the irresponsible press release. It seems to describe some very interesting functions of Muller glia, that help mitigate the problems caused by putting detectors (retina) behind layers of light-scattering cells.


The press release is what you say, but the actual article is really interesting.

Well I was a bit unfair; it’s more of an OTT blog post than a press release as near as I can tell. But it’s unfortunately bad.

It is, and it could be an example of a nice kludge, of the kind we see regularly in animal physiology and development. It could be interesting to look into the evolution of Muller glia.

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You mean the eye having a literal blind spot in the middle of your field of vision that your brain fills in by interpolating the surrounding light, literally causing a small part of your visual field to constitute an illusion is “a good functional reason?”

And they’re right. The fact that there are all sorts of compensatory mechanisms in place to still make our eyes into useful sensory organs, despite this painfully obvious flaw of wiring (which still only makes sense as the product of the historical outcome of how the eye first evolved) doesn’t change the fact that we literally have blind spots in the middle of our field of vision. Our genome literally carry genes coding for proteins that have evolved to compensate for the drawbacks of this ridiculous structure, genes that simply wouldn’t be needed if the wiring hadn’t been inside-out, as the light wouldn’t have had to pass through these cells in the first place.

Again, the fact that partially compensatory solutions to these obvious drawbacks exist do nothing to show that the backwards wiring of the retina resulting in a literal blind spot is not actually a poor design. If anything can at all be said to constitute a poor design, then that can.

I will also note the apparently prototypical contradictions between various ID-creationist rationalizations about poor-vs-good design. On the one hand we’re often told creationists aren’t saying everything should be perfectly well designed (they always say they’re not predicting there should be ZERO junk-DNA, for example), then on the other hand they will protest at length when we point out such junk DNA.

This example with the backwards wiring of the retina in the vertebrate eye is no different. Again creationists are now insisting this is all somehow making the eye better, because they can’t apparently accept the idea that something in biology isn’t perfectly well designed. Admitting to there being some flaw in the structure of human biology is something they just can’t get themselves to when it comes down to it.

It isn’t exactly bad design either :slight_smile: .


If the inverted retina is the best design then why don’t cephalopods have that design?


Sure, because it isn’t design. A competent designer probably wouldn’t have done it that way.

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