Eyes are among the great challenges to those who insist that unguided, naturalistic evolution created all living things. Eyes are complex devices that display engineering design skill. A significant problem for naturalists is that some very complex eyes appear early in the fossil record, such as the trilobite eye. Each animal has eyes well-designed for the life they live. That is certainly true of the amazing human eye.
Many things about human eyes make them amazing. One of those is the cornea, the clear front covering of our eyes. Corneas must be perfectly clear to allow light to pass through for an unobstructed view of the world around us. Because of the need for complete transparency, they have no blood vessels. Our corneas get their nourishment from the aqueous humor (the liquid inside the eye) and the tear fluid on the outside. They get oxygen from direct contact with the air.
Corneas must be designed to fit a curving surface full of a fluid which maintains the critical pressure inside the eye. However, there is a problem with the cornea being exposed to the air with all of the contaminants it contains – pollen, dust, chemicals, and grit. Corneas can become scratched. Over time, any surface exposed to dirt and grit, and sometimes bumps and blows, can get tiny scratches. How is it possible for corneas to remain transparent with so much abuse?
When you cut your skin, as the cut heals, scar tissue forms. Scratches in our corneas must heal without scar tissue. When the outer layer of the cornea gets scratched, the surrounding cells move toward one another and close the scratch leaving no scar tissue. This is only one feature of corneas which consist of five different layers each having an important function and showing evidence of design.
Think what it would be like if scar tissue formed every time the surface of our corneas got scratched. By the time we reached middle-age, we would certainly be looking through cloudy lenses. If you can read this, you should be thankful for just one of the features of the amazing human eye!
–Roland Earnst © 2018