hi 19,
I don't even think that the eye is that well 'designed'.
It can be 'disarmed' very easily by even atiny bit of dust.
Two weeks ago I was taking my contact lenses' out and I managed to cause a small corneal abrasion on the surface of my eye, the next day it was absolute agony LOL , I was off work for a week.
I am sure I read somewhere about the eye perhaps evolving from light sensitive cells, I am not sure but it may have been Dawkins that wrote about this theory.
Brian.