The human eye is able to focus automatically, using a self-adjusting aperture......?

............It can focus in both bright sunlight and minimal moonlight. Some ID proponents say that evolution implies that living organisms are not complex or intricate. They say the human eye, an extremely complex organ, is a perfect example of why evolution cannot be valid; it simply could not have been designed by altering one gene at a time. Based on the information. Does the existence of the human eye provide evidence against evolution? Explain/defend your answer.