The Green light is a daisy's house. This helps Gatsby remember his american dream of marrying Daisy.
"He stretched his arms out toward the dark waters in a curios way, and, far as I was from him, I could have sworn he was trembling. Involuntarily, I glanced seaward-and distinguished nothing exempt a single green light, minute and far way, that might have been the end of a dock.
The eyes of T.J Eckelburg rempresent God overseeing the Valley Of Ashes
"Standing behind him, Michaelis saw with a shock that he was looking at the eyes of Doctor T.J. Eckleburg, which had just emerged pale and enormous, from the dissolving night. "God sees everything." repeated Wilson."