The Evolution of the Human Eye   Sean D. Pitman M.D.  © May.
2001  Updated October 2008            Table of Contents
Numerous Gradations           A Closer Look     Now, what if we
do not have to explain the origin of the first light sensitive
"spot."  The evolution of more complex eyes is simple from that
point onward. . .  right?  Not exactly. (See discussion of the
Nilsson and Pelger paper below):    The Nilsson and Pelger
Theory of Eye Evolution     In 1994 Nilsson and Pelger published
what was to become an oft-referenced classic paper on the
evolution of the complex camera-type eye starting from a simple
light sensitive eyespot.22  In their paper they argued that a
series of insensible gradations, 1829 steps in all separated by
1% changes in visual acuity, could be crossed by an evolving
population in about 350,000 generations - - or around 500,000
years.  The following figures illustrate their theory: 
diagram 1    The illustration above is layered with a dark
backing and has a translucent e