Backward Wiring of Eye Retina Confirmed as Optimal
You can’t get any better performance out of an eyeball than the way it’s designed, backward wiring and all.
The “mystery of reverse-wired eyeball” is solved, according to a press release from the American Physical Society. Erez Ribak, of Technion – Israel Institute of Technology, believes that, for the first time, his research team has discovered why the photoreceptors are positioned behind a tangle of neurons.
Previous experiments with mice had suggested that Müller glia cells, a type of metabolic cell that crosses the retina, play an essential role in guiding and focusing light scattered throughout the retina. To test this, Ribak and his colleagues ran computer simulations and in-vitro experiments in a mouse model to determine whether colors would be concentrated in these metabolic cells. They then used confocal microscopy to produce three-dimensional views of the retinal tissue, and found that the cells were indeed concentrating light into the photoreceptors.
“The retina is not just the simple detector and neural image processor, as believed until today,” Ribak added. “Its optical structure is optimized for our vision purposes.” The discovery of Müller cells acting as light concentrators and waveguides dates back to May 2007 (cf. 5/02/07, and update on 7/23/14).
The counter-intuitive “backward” wiring has long been used by evolutionists as evidence for bad design, the argument being that a Creator would never design an eye this way. It must have evolved, they claim, because natural selection is a “tinkerer” that cobbles together parts just to get something that works.
Surprisingly, this same article that found optimal structure in the retina also attributed it to evolution. The press release begins,
From a practical standpoint, the wiring of the human eye – a product of our evolutionary baggage – doesn’t make a lot of sense. In vertebrates, photoreceptors are located behind the neurons in the back of the eye – resulting in light scattering by the nervous fibers and blurring of our vision. Recently, researchers at the Technion – Israel Institute of Technology have confirmed the biological purpose for this seemingly counterintuitive setup.
It’s not clear if those are Ribak’s views or if the appeal to evolution was invented by the press release author. His findings are to be presented at the 2015 APS Meeting in San Antonio, Texas, on March 5.
Update 3/13/2015: On The Conversation today, Erez Ribak in person has explained why the eye is “wired backwards” for several good reasons. What’s new is how the retina optimizes reception by color. Since blue predominates in daytime light, we don’t need it amplified, so most of the blue wavelengths scatter in the eyeball and retinal blood vessels to the rods. That’s also why there are fewer blue-sensitive cones in the retina. Green and red, however, need amplification. Experiments with guinea pig retinas and computer models showed some surprises:
Further computer simulations showed that green and red are concentrated five to ten times more by the glial cells, and into their respective cones, than blue light. Instead, excess blue light gets scattered to the surrounding rods….
The result was easy to notice: in each layer of the retina we saw that the light was not scattered evenly, but concentrated in a few spots. These spots were continued from layer to layer, thus creating elongated columns of light leading from the entrance of the retina down to the cones at the detection layer. Light was concentrated in these columns up to ten times, compared to the average intensity.
Even more interesting was the fact that the colours that were best guided by the glial cells matched nicely with the colours of the cones. The cones are not as sensitive as the rods, so this additional light allowed them to function better – even under lower light levels. Meanwhile, the bluer light, that was not well-captured in the glial cells, was scattered onto the rods in its vicinity.
These results mean that the retina of the eye has been optimised so that the sizes and densities of glial cells match the colours to which the eye is sensitive (which is in itself an optimisation process suited to our needs). This optimisation is such that colour vision during the day is enhanced, while night-time vision suffers very little. The effect also works best when the pupils are contracted at high illumination, further adding to the clarity of our colour vision.
Perhaps the best proof that retinas are well-designed is shown by attempts to mimic them. PhysOrg tells about attempts at one institution to create “image sensors that behave like biological retinas.” The interviewee says, “Our sensor, on the other hand, is based on the ‘Dynamic vision sensor’ (DVS) principle, which is itself inspired by the way biological retinas work.” It’s very hard to imitate, though. “Well naturally real biological retinas are more complex, with many different types of pixels (cells) which are also communicating with their neighbours,” he explains. “Such properties would be very complicated or impossible to develop with standard CMOS technology.” How, then, could a blind process of evolution come up with an image sensor vastly superior to what our top-notch engineers are capable of designing with purpose and planning?
Evolutionists always play the heads-I-win tails-you-lose strategy. If it’s non-optimal, evolution wins. If it’s optimal, evolution wins. They’ve designed their rhetorical bag of tricks to be ready for any circumstance. This was a prime case of dysteleology in their repertoire that has been shot out of their hands. Don’t trust their hand-waving antics to explain it away as a result of “evolutionary baggage.” Their baggage is empty.
Solomon, the wisest of men, said, “The hearing ear and the seeing eye, the Lord has made them both” (Proverbs 20:12). It took humans almost 3,000 years to see how God designed the structure of the eye to reduce scattering and concentrate the light onto the photoreceptors for optimum vision. Our response should be humble worship, not storytelling about blind processes creating sight.