Darwin used the human eye to illustrate “organs of extreme perfection and complication.” To neo-Darwinists*, however, the human eye is a case of ill-designed optics. So what gives?
First, while evolutionists believe the verted retina in invertebrates (e.g., squids) is superior to the inverted retina in vertebrates (e.g., humans), precisely the opposite is true. As a case in point, the inverted retina features a highly sophisticated neurological feedback system that enhances contrast without sacrificing detail. Even the oft-mentioned blind spot is not blind in that the dual eyes of a vertebrate provide overlapping fields of vision.
Furthermore, as has been well said by historian Henry Petroski, “All design involves conflicting objectives and hence compromise.” As such, constrained optimization invokes the art and science of compromise in a sea of conflicting objectives. For example, a theater-size screen might be optimal for watching movies—but hardly at home. Evolutionary biologists seem fixated on individual functionalities while forgetting functional interconnectedness. Constrained optimization requires compromise for the good of the whole.
Finally, to pontificate that the eye is poorly designed is patently shortsighted. Advancements in biology have demonstrated even straightforward structures in the eye to be enormously complex. In Darwin’s day, tears were thought to be quite simple. Today whole books are devoted to them. As marvelous mixtures of water, mucins, oils, and electrolytes, they not only thwart infection but moisturize the cornea and continuously cleanse the eye of pollutant particles.
Darwin was right. Human eyes are organs of extreme perfection and complication. Even now a vast number of impulses are traveling from your eyes through millions of nerve fibers transmitting information to a complex computing center in the brain called the visual cortex. Linking visual information from the eyes to motor centers in the brain is crucial to the very process of daily living. Without the coordinated development of the eye and brain in synergistic fashion, the isolated developments of either are not only meaningless but counterproductive. The eye was flawlessly designed by God to work in synergy with the entire body.
Source (and for further study), see Henry Petroski, Invention by Design: How Engineers Get from Thought to Thing (Cambridge, MA: Harvard Universtiy Press, 1996); also Hank Hanegraaff, The FACE That Demonstrates the Farce of Evolution (Nashville: Thomas Nelson, 2001).