I was never a fan of Babylon 5, but I did catch a few episodes.
Hate to go off-topic, but while we're on the subject, I remember watching this one episode of B5 when it was on TNT a few years ago. In one scene, the guy who played the reptilian leader, was missing one contact lense and you could see his human eye while the other one was covered up with a reptilian eye. In the next shot he was back to normal. So it must have been a continuity error, but how could they have forgotten to put his other contact lense in?
If he's talking about G'Kar (spotted head, reddish face, pronounced chin, sunk-in eyes), they story behind that could be that the episode you saw was after he had lost his eye.
G'Kar was captured, and had an eye put out. When he was rescued, an electronic eye was put in place, but the only one's available at the time were in a human-blue color. He spent a few episodes with one red and one blue eye while he waited for a new eye that would match.
I think I'm talking about G'Kar, but I dont think it was part of the storyline. From what I remember he was chatting with a human during a scene and then all of the sudden, between shots, one of his eyes turned human and then back. I could be wrong.