Wow! These are wonderful images. I love close head shots, and with Jessica's eyes you have done a brilliant job.
As someone earlier had mentioned, I noted too that in the first image her right eye (closest) is brighter than her left, but yet in the second image her left eye (also closest) is brighter. Could it be from the jacket that you were wearing?
The only other thing is that the last image seems to have a slight green cast to it. This is apparent in the snow behind Jessica, and the slight change in skin pallor.
But still, Jessica's eyes are simply beautiful to behold, and you have done very well to capture that of her.