Hi bullet

Looks like a good start
I have attached a drawover image to explain a bit more of what I am about to say:

It's a bit hard to see, but it looks like if the eyeball is a regular sphere, while the cornea( the transparent bit where you see the iris through) needs to bulged a bit:
https://www.bbc.co.uk/schools/gcsebit...estructure.gif

Second, I have found that a well proportioned eye keeps more or less to the rule of thirds, the eyeball is 3 times as large as the iris, the iris in turn is 3 times as large as the pupil ( at least in a neutral position).

it looks like you need to tighten the transparency ramp on the sphere a bit as well, so that you don't see the end of the iris , normally you'd let the ramp slightly overtake this edge so that you have a seemingly smooth transition with nice shadowing

I have attached a testrender I did not so long ago ( for a certain wizard ), while it's most definitly not the best eye ever it shows some reference to look at

good luck bullet