Board Thread:Metal Gear Solid V/@comment-25277765-20140831060343/@comment-1504072-20140831105629

Liquid's eyes are green in concept art only, which were not clear in the final game for graphical limitation reasons. Solid Snake's were unknown, because his concept art wasn't too clear. I'm not sure if Twin Snakes made a decision on eye color, as they seem to appear grey in screenshots. For Twin Snakes, Meryl's eye color was hazel I believe, reflecting MGS1 concept art, yet the designers chose to make them blue when she appeared in MGS4.