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Latest research shows the eye is an example of optimal design – not poor design as evolutionists often claim.

One of Richard Dawkins’ famous arguments against intelligent design is his claim that there are many examples of sub-optimal design in creation.

The classic example he gives is that a human engineer would reject the eye because of its imperfections, so it can’t be the work of an intelligent designer. Consequently, the so-called poor design of the eye has been cited endlessly by other atheists as an argument against God.

In his widely acclaimed book The Blind Watchmaker, Dawkins devotes much attention to this organ as a prime example (as he supposes) of only apparent design. And so he denigrates the Creator for bungling (in his view) the design of the retina with its ‘back-to-front’ wiring, which he labels as a “revealing flaw”.

The eye is still much better than anything engineers have been able to design, so it’s a little premature to reject it, but is the vertebrate eye really a bad design? As time goes by, researchers are refuting Dawkins’ argument. In fact, so many of nature’s designs are being admired that a whole new branch of technology has sprung up to copy them for human benefit: biomimetics or biomimicry. And the icing on the cake is that evidence is also coming to light of the brilliance of eye design.

First, in 2010, a paper in Physical Review Letters, ‘Retinal Glial Cells Enhance Human Vision Acuity’1, began to dismantle Dawkins’ claims. It found that special “Müller glia cells” sit over the retina, acting like fibre-optic cables to channel light through the optic nerve wires directly onto the photoreceptor cells. Dawkins had asserted that the vertebrate eye is flawed because the optic nerve runs over the retina, creating a ‘blind spot’. In fact, the funnel-shaped Müller glia cells ensure that there is no loss of vision due to the route of the optic nerve. Instead, the Physical Review Letters paper cited the retina “as an optimal structure designed for improving the sharpness of images.” New Scientist magazine explained that glia cells “act as optical fibres, and rather than being just a workaround to make up for the eye’s peculiarities, they help filter and focus light, making images clearer and keeping colours sharp.”

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Then, in 2014, came more research that should finally lay Dawkins’ argument to rest. A paper2 in Nature Communications, “Müller cells separate between wavelengths to improve day vision with minimal effect upon night vision,” revealed more about the eye’s optimal design. Not only do Müller cells behave like optical fibres, funnelling light down the optic nerve, but they are also sensitive to certain wavelengths of light to ensure that these wavelengths are channelled to the correct retinal cells.

The authors refer to the arrangement as “a novel mechanism” and clearly demonstrate that the eye does not have sub-optimal wiring. Instead, “the wave-guiding properties of Müller cells are wavelength-dependent in a manner that improves cone-mediated vision while minimally impeding rod-mediated vision.”

It’s a clever balance that improves daytime vision without hindering night vision: “The shape of the Müller cells – wide at the top where it collects light, and narrow at the bottom where it delivers light to the rods and cones – presents a potential optimisation trade-off between day vision (which depends more on efficient light transmission to the cones) and night vision (which depends more on efficient light transmission to the rods).”

The paper concluded: “Therefore, light propagation by Müller cells through the retina can be considered as an integral part of the first step in the visual process, increasing photon absorption by cones while minimally affecting rod-mediated vision.”

There are other so-called flaws in the eye that research has revealed are actually an advantage. For example, most invertebrates have a verted eye (where the rods and cones face the light source), whereas most vertebrates possess an inverted type of eye (where the rods and cones face away from the source of light). Anti-design writers like Dawkins have said that if a camera designer suggested the inverted system he would have been fired. But no evidence exists that the verted eye is superior to the inverted eye. The sensitivity of the existing human inverted design is so great that even a single photon is able to elicit an electrical response (Baylor, Lamb, and Yau, 19793).

The importance of these discoveries has been recognised by experts in optics. An astounding article at Phys.org4 in 2014 analysed the Nature Communications paper. It concluded that the idea that the vertebrate eye is a bad design “is folly” because “having the photoreceptors at the back of the retina is not a design constraint, it is a design feature.”

Mr Dawkins, please take note.

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This article was taken from The Delusion of Evolution.