I found 3 adults in the exact same spot in eastern Kansas. 2 had very dark eyes, darker than the North Carolina one in the picture. The other one had reddish eyes, kind of like some yellow or glades rats. I think I've found 1 or 2 in Arkansas or Missouri that had the silvery eyes, but I couldn't tell you exactly where. While like these other guys are saying, the eye color can vary in eastern populations, however most of the ones I've seen with the silvery eyes were from the eastern part of their range.