I do it with only a single ocular image (eye, eyebrow, and surrounding skin texture) rather than the full face. Using 1:1 matching environments are common for NIST challenges.
http://www.cs.cmu.edu/~vboddeti/papers/ijcb_2011.pdf
I have two more in the pipe (one still awaiting acceptance, and the other is accepted but yet to be added to IEEEXplore)