Gatsby stands absorbed in his observation of the point where the green light appears at Daisy’s house, even though Daisy is standing at his side. He’s focused on the light that symbolizes her, as he has been for so long, instead of interacting with her while she’s actually present. The green light is losing significance for him now that he and Daisy are interacting, and Fitzgerald writes “His count of enchanted objects had diminished by one.”