Duplicate this model and transform it in the second one: the iris, pupil and white of the eye. For that, you will flatten the camber almost completely in the previous piece. Select the edge ring in red...
...connect and create a new edge loop like this:
Pull the vertexes (or extrude the faces) of this area, forming a hole, that is the pupil:
Here is the perspectvie view (the iris is ALMOST flat, but it has an area slightly deepened):
Here, the two pieces in the side view, wire/SubD:
And here, in perspective view:
To make the cornea shader, use the configurations posted left (MAYA) or approximate this result using MAX. Clue: for specular, choose the white color however, force to use 2 times whiter (adjusting V from HSV for 2, for instance). Use a low reflection value(0.037, in MAYA) and 1.2 value for raytrace/refraction:
For the other piece, modeled last, use the texture that you made using my other tutorial and a very low especular level and very "open" highlight (almost opaque). Use planar/frontal map for this texture:
If you want to include some volume in the veins, hide all iris layers, change image to grayscale mode (or desaturate) and use this image as the bump map:
You will also be able to add a self-ilum map or incandescence in the iris, using a map as this (very low value):
Here is the "final" version:
a) use an area light to simulate window reflections;
b) for cornea, turn off the cast shadow. This will save a lot of render time in your scene.