In 1872 Charles Darwin's 6th edition of The Origin of Species was published. In Chapter VI: Difficulties of the Theory, Darwin wrote that the idea of natural selection producing an eye seemed "absurd" before describing an evolutionary process of a complex eye developing over time from a light sensitive nerve:
To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree.
More recently evolutionists have described the eye as definite proof that intelligent design did not occur.
Kenneth Miller writes that "visual quality is degraded because light scatters as it passes through several layers of cellular wiring before reaching the retina."
Regarding the human eye, Richard Dawkins writes in The Greatest Show on Earth: The Evidence of Evolution, "Once again, send it back, it's not just bad design, it's the design of a complete idiot."
Dawkins complains "the retina is back to front" and "wires that carry their data somehow have to pass through the retina and back to the brain."
So how do supporters of intelligent design respond to these arguments? With class and and armed with facts.
According to Salvo Magazine:
To achieve the high-quality vision that vertebrates need, retinal cells require a large blood supply. By facing the photoreceptor cells toward the back of the retina, and extending the optic nerve out over them, the cells are able to plug directly into the blood vessels that feed the eye, maximizing access to blood.
Westmont College biologist George Ayoub analyzed Dawkins and Millers critique of the eye and designs for removing the blind spot in the eye.
In the journal Origins & Design, Ayoub writes, "In trying to eliminate the blind spot, we have generated a host of new and more severe functional problems to solve. Our 'repair' seems far worse than the apparent flaw we wanted to fix."
For more information about the design of the eye, check out the article Eyeballing Design: "Biomimetics" Exposes Attacks on ID as Poorly Designed.