HERE IS THE REAL ANSWER.
The cast and staff at splinter cell did relize that the lense does not glow green, ofcoarse. But you see if you didnt know any better that glow is his logo. You see ubisoft wants something that you would remember about Sam Fisher and the game. Thats why in most of your trailers in because with darkness and then you see a 3 little lights go on that are green. Ubisoft is tryinh to stick that image in you head so that when you see it somewhere else your like....."splinter cell".