Question

A human eye is an example of a simple machine found in the human body.

Answer 1

Hardly. The classical simple machines were defined as the lever, wheel, inclined plane and screw. The eye is a fiendishly complex machine, particularly when you take into account it does much more than just focus and appropriately stop light -- it also does a fair amount of basic image processing before the results are sent to the brain.

Answer 2

I agree 100% with @Carl_Pham on this one!

Furthermore it's been discovered that some of the cells in the eye (which were previous just thought to transmit the signal from the rods & cones, are in fact able to detect quantum states of light). Proof? Migrating birds actually navigate long distances using this electromagnetic-state detection, function like a subconscious compass: http://www.newscientist.com/article/mg20927963.000-quantum-states-last-longer-in-birds-eyes.html

The eye is arguable on of the MOST complex machines nature has ever developed. And while human eyes may not be as evolved and expertly adapted as in some birds (i.e.: eagle eye) it's nonetheless incredibly complex.

The motion of the eye alone pivots on a low friction (slippery) surface inside a socket controlled by several different muscles: http://en.wikipedia.org/wiki/Muscles_of_orbit

To test all of your eye's movement muscles, "draw" a letter H visually with where you look.