User blog comment:Tiredman2/Mass Effect Plot Holes and Contradictions/@comment-4950455-20120903001020/@comment-4953843-20120903072608

as to the issue of why not 4 eyeholes if the helmets were batarian knockoffs, we know they treat eyes like some sort of status symbol. notice the eyeholes don't even correspond to the approximation of batarian eye positions.

probably optical sensors as opposed to actual eyeholes.