Just because your wife's eyes are brown, does not mean that the blue gene is not present in her makeup, just that brown is the color that dominated...IF she does have a blue gene present but not obvious then there would be a one time out of every 2 odds that your children (with your eyes blue) could be blue eyed even though she has brown eyes showing.
If she had no presence of the blue eyed gene, even masked, then your children would have ZERO CHANCE of having blue eyes, her brown color would dominate over your blue.
jd