Diamond Eyes (Boom-Lay Boom-Lay Boom) Lyrics

Lyric discussion by stumlad 

Cover art for Diamond Eyes (Boom-Lay Boom-Lay Boom) lyrics by Shinedown

I don't think the song is stricly about being a soldier (though it works since it fits with the movie). I think it's basically a metaphor for going out an taking a risk instead of holding back and regretting it.

By "Diamond Eyes", I'm thinking that he's saying he's able to see more clearly (really good diamonds are known for being clear with no color, etc).

I would agree that the song isn't strictly about soldiers, and also about the clear eyed view of diamonds. I think there is another meaning diamonds in this context though. Diamonds are the hardest substance on earth. The artists are trying to indicate something about the nature of the person being sung about. They are talking about a cynical world view, a realism. The standard form of the phrase would be "hard eyed" or "Steely-eyed".