Assuming there was an accurate way to assess lying with the color of the eyes indicating it is a lie.
Well, is it a lie if it's technically truthful?
Consider the following scene from the Comic Book story "52" from DC:
During the course of the series, Superman has not been active because he lost his powers just prior to the story's beginning. A new hero named Supernova has appeared in Metropolis and Clark Kent landed the first interview with him. Lex Luthor thinks that Superman is merely hiding and waiting for Luthor to return to his old tricks, so he has Clark Kent kidnapped and drugged with a potent truth serum (and yes, it works). The the following (paraphrase) conversation occurs:
Lex: Who is Supernova?
Clark: I don't know.
Lex: Did he seem familiar?
Clark: A little, but I can't place him.
Lex: He reminds you of Superman, doesn't he.
Clark: Laughs in Lex's face I could tell from our meeting that Supernova is definitely not Superman.
Now, keep in mind, Clark doesn't lie at any of these points... but he doesn't clarify anything about the lie. Lex Luthor wants to know who Supernova is, but Clark doesn't know, though does admit he seems familiar (I'd spoil the story by revealing, but Clark met Supernova's unmasked personality a while back. Luthor would also know that since he covered some heroes and superman stories, a flying caped man in a mask could seem familiar to Clark, given his work.). Lex then asks if Supernova reminds Clark of Superman.
Now, for the uninitiated, Clark Kent has some very good reasons as to why he knows that Supernova is not Superman, but doesn't want to tell Luthor. So his response is given in a truthful statement. Clark can truthfully say that having met, he could tell that Superman is not Supernova. After all, he's gotten to know Superman quite well over the years of covering him.
So have your character tell the truth... but in a way that is deceitful.
Take another famous moment in real life history: "I did not have sexual relations with that woman."
Legally that is a true statement... under Washington D.C. laws at the time what was alleged to have occur between the speaker and "that Woman" was not part of the legal definition of "sexual relations". The speaker would have known this, but was hoping that the people hearing him say that would would consider the specific allegation under the common term "sexual relations".
As a final note, when writing this character, the proper frame of mine is reflected in this wonderful conversation from Deep Space 9:
Brashir: But which of the stories [about Garak's banishment] is true.
Garak: My dear doctor, they're all true.
Brashir: Even the lies?
Garak: Especially the lies.