I'll just paste what I said on DA:
------------------------------------------------
It's pretty good, but there are a couple things you might consider improving upon:

It looks like the picture of the eye you found was smaller than the actual size you used, so you had to make it larger, which is fine. However that takes away from the smoothness of the eye - it looks kind of pixellated, especially around places like the eyelashes where there is more contast with the skin behind. You might consider some type of smoothing filter, although those can make things look cheap. But it's only noticeable to a close inspection. I enjoy making wallpapers especially using photo manips, so I noticed. If it was a little crisper it would be better. Next time maybe try to find a high definition image that is too big - scaling down some preserves smoothness more easily, but when you are going the other way you have less to work with.

I'm not quite sure what the white streaked lines sort of coming out of the iris are supposed to be, but they don't look very natural, especially because they appear to come out of the eye and yet do not conform with other things in the eye - they are behind the iris and yet come over the eyelashes and the area underneath. Kind of distracting, I guess.

I kind of like the contrast of the iris, it draws attention to the middle. The firey glow is cool, although indeed I think something like more blue would "fit in" more, but really all of this is subject to the artist himself's eye. It's also noticeable that the eye has no pupil. Whether that was intentional or not, I dunno. It's fine for a wallpaper because the contast is more closely reserved and in a standard desktop it would not hinder much.

All in all it's a pretty good image, but I just decided to critique it a little more closely. I hope you don't mind. If you don't take it apart piece by piece and instead look at the whole, it's cool. Nice job.