Green-Eyed

Coach Carter - Give up Mr. Cruz

In a development not seen in any other version of the Green Lantern mythos, 

John Stewart's eyes glow green as a side effect of his fifteen years 

of exposure to the power ring's radiation

The glow fades when the ring runs out energy 

or if he is physically separated from the ring. 

Bruce Timm said this was done to give Stewart's face 

a more visually interesting look, 

as they decided to stick with the comic book tradition 

of depicting John Stewart without a mask. 

By many accounts, the ring is also effective against yellow, 

contradicting an age-old weakness of the Lantern Corps. 

This is in continuity with the earlier appearance of Kyle Rayner on Superman: The Animated Series.