Got some help from Åsa today, which was great, since it was a pain in the ass trying to get my own eye in focus like this and operating the camera at the same time. Also, she has really pretty blue eyes.
She's holding up a Raynox 150 macro converter. It was not all that easy getting the whole eye in there and getting it sharp wide open. I didn't want to bore her to death (she's always keen to help as long as it's all over very quickly) so it's not perfectly aligned or tack sharp but I still like it.