You probably already know all this, but I think it's interesting so I'll write a bit. The eye has always intrigued me.
The eyes are a strange one. If we were to build something, we build it completely logically. However, the way the eye works was built randomly, so each part doesn't necessarily work all in one manner.
For example, the six million cones
in the Fovea centralis section (macula) of the retina pick up the three green (45%), blue (45%) and red (10%) cone wavelengths are generally thought to be used for daytime vision.
The rods
which are 20 times more numerous and are situated around the periphery of the macular are thought to be for night vision. That's why we see things at night better out of the 'corner of our eye'. There are far fewer rods in the cone section within the Fovea centralis depression.
However, rather recently it has been shown that we also use the rods for motion detection, so we also see motion better from the corner of our eye.
Here is a cool page on 'Tricks of the Mind' that I found interesting.
http://www.parascience.org.uk/misc/method/tricks.htm
Years ago I experimented a lot with color theory. I found that one could stare at a room, then close your eyes and see the whole room there.
I also realized how large an area of our vision is blocked by our nose, yet we don't see it at all.
In a similar way, there is the huge area on the retina that has no receptors where the optic nerve is. When you project that small circle outward, at about 2 feet out the circle that can't be seen is almost 2 inches around. If you take that out to hundreds of feet, that would mean that we must not be seeing a circle something like a hundred feet around (too lazy to do the math right now... but you get the idea) yet we see a continuous image. We don't see a big black dot.
I've mapped my optic nerve many times before.
To map it, you draw two dots on a piece of 8 1/2 x 11 piece of paper with a black sharpie marker about 5 inches apart. You then place the paper onto a table, close the left eye and stare at the left dot with the right eye, never taking the right eye off that dot. When I move my eye towards and away from the paper, the right hand dot disappears when the paper is about a foot from my eyes, and doesn't reappear again until the paper is about 2 3/4 feet away. If you take a pencil, without moving your left eye from the left dot, and you scribble a circle over the right dot area you can map the size of the blank optic nerve area at that particular distance from the eye. The further away, the bigger the dot of course.
Another interesting thing about the optic nerve area, if there is a checkerboard pattern out there, we somehow can supply the rest of the checkerboard with our minds to fill in that blank hole. But, even if there's something as difficult as a face, somehow our mind fills in the rest of the face as well.