Creationists have long countered such arguments by pointing out several important reasons why the retina is set up the way it is2,3. Among these is the need for the photoreceptors to be in close contact with the retinal pigment epithelium (RPE) layer of the retina, which performs numerous vital functions, including the continual regeneration of the photoreceptor cells, the blocking or breaking down of harmful substances, the transfer of nutrients from the choroid to the photoreceptors and other cells in the retina, and the absorption of excess light. The choroid, in addition to providing the nutrients for the retina, acts as a heat sink to remove the excess heat generated in the RPE, thus protecting the photoreceptors from heat damage. Both of these layers need to be in close proximity to the photoreceptors to ensure adequate protection and efficiency, but both are opaque. Were they put in front of the photoreceptors, as a verted retina would require, they would block most of the light from ever reaching the light sensitive cells.
Creationist (and some evolutionist) ophthalmologists who have studied the problem in depth have concluded that the inverted design of the vertebrate retina is the best arrangement considering the environments in which vertebrates live and the contraints placed on the design by the physical properties of light and the "seeing" process. Rather than being evidence of poor design, it demonstrates the ingenuity of the Creator in designing an eye that reaches the perfect compromise between all the conflicting variables.2,3
Evolutionists point to the verted retinas of invertebrates, especially cephalopods, as the perfect or correct design. Creationists disagree. They point out that contrary to the poorly designed claim, our eyes provide us with excellent vision. While the verted retina is suitably adapted to the undersea environment of the squids, octopi, etc. that possess it, there is no evidence it would work as well for land-dwelling vertebrates. In fact, since it lacks some of the numerous protective devices built into the vertebrate retina, it would probably be more susceptible to damage, and thus prove a much poorer design for our environment.2,3
While the above arguments are more than enough to discredit the poor design claim, new research has turned up even more powerful evidence for the superb design of the vertebrate retina4,5,6,7. It turns out that some of the cells in front of the photorecptors that were previously thought to be for structure and support only actually act as a fiber optic plate of sorts, transferring light through all the obstacles with very little distortion. These cells, called Muller cells, have funnel-shaped ends, which provide for even better collection of light in addition to allowing room for all the nerves to pass between them without blocking the light. This structure completely does away with the supposed disadvantage of the nerves blocking the light, which was not much of a disadvantage to begin with.
Once again, real science supports the creationist worldview, while posing serious problems for evolutionary theory. Despite all their accusations of poor design, evolutionists themselves have no explanation for how such a complex, perfectly balanced system could have evolved by chance8. In reality, their objection is not even based on science, but on their own faulty ideas of what God could or would do or not do. Not being able to provide a scientific explanation, they have resorted to illogical theological objections.
"Because that which may be known of God is manifest in them; for God hath shewed it unto them. For the invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse: Because that, when they knew God, they glorified him not as God, neither were thankful; but became vain in their imaginations, and their foolish heart was darkened. Professing themselves to be wise, they became fools."
Romans 1:19 - 22
Remember, "the foolishness of God is wiser than men." (1 Corinthians 1:25) The case of the inverted retina is ample proof of that. Who are you going to trust?
- For one example, see "Creationism Still Blows!", by "Nella" on the Jalenack blog. For a more official version, see the quote from Richard Dawkins in reference 4 below.
- Gurney, Peter W. V.,
"Is our ‘inverted’ retina really ‘bad design’?"; http://www.creationontheweb.com/content/view/1683/, Accessed 9/01/2007. First published Journal of Creation 13(1):37–44, April 1999.
- Bergman, Jerry, "Inverted Human Eye a Poor Design?"; http://www.asa3.org/ASA/PSCF/2000/PSCF3-00Bergman.html, accessed 9/01/2007. From Perspectives on Science and Christian Faith 52 (March 2000): 18-30.
- For the creationist perspective that inspired this post, see Sarfati, Dr. Jonathan D., "Fibre optics in eye demolish atheistic ‘bad design’ argument", (Creation Ministries International, 8/21/2007); http://www.creationontheweb.com/content/view/5214, accessed 9/01/2007.
- For the abstract of the original article, see "Müller cells are living optical fibers in the vertebrate retina", on the Proceedings of the National Academy of Sciences website.
- For a popular-level news story, see "Living Optical Fibres Found in the Eye," by Lucy Sherriff from The Register.
- For a more detailed look at the experiments, see "Müller cells: Nature’s fibre optics", on the Neurophilosophy blog.
- For more instances of brilliant design in the eye, see Wagner, Tom, "Darwin vs. the Eye", http://www.answersingenesis.org/creation/v16/i4/eye.asp, accessed 9/01/2007. First published: Creation ex nihilo 16(4):10–13, September 1994.