Scott Fitzgerald rarely puts characters or events that have do not either have an underlying message or support in the character development of the lead characters. Therefore I was confused as to what Owl Eyes represented. Clearly he is significant as he is one of the few people to show up to Gatsby's funeral. So what is he supposed to represent or rather what message is Fitzgerald trying to deliver through Owl Eyes?
On the surface, Owl Eyes is a perceptive character. He sees things that others miss. In reality, though, he's more easily fooled than anyone.
The large glasses, of course, tie him to the Eckleburg billboard. There's a continuous contrast between surface and reality in the book, with the nagging question of how to tell the difference. Bigger glasses? Eckleburg's are the biggest, and they don't see what's going on right in front of them.
We first meet "Owl Eyes" in Gatsby's library. His real name is never given, but he may represent Ring Lardner. He's looking at volume one of Stoddard's Lectures, one of those books nobody reads but claims they have. He notices it's a book, not a prop, but the pages haven't been cut. (In those days printers saved time by folding up large sheets and binding those together, which left the edges of the book a series of folds rather than pages. To read, then, you needed a paper knife to cut through these folds.) Gatsby has never read the book, and if he hasn't read volume one, he hasn't read any. The book is real, the house is real, but Gatsby is not. Owl Eyes sees that the book is a book, but that's all. He sees the surface but not the reality. "You can't judge a book by its cover" is inverted--he sees inside the book but not inside its owner.
We next meet Owl Eyes in the driveway after he's crashed his car. He cheerfully admits he doesn't know how to drive. However, he's managed to block everyone else from leaving, and he has no clue about how to fix the situation. Again, he sees the surface (he knows how to drive) but not the reality (he can't deal with the consequences of a crash).
Finally, he shows up at Gatsby's funeral. The only person who feels that much sympathy, besides Nick, is the person who can't see. Gatsby is a cardboard cutout. Owl Eyes has come to his parties and believes the facade is real, but Gatsby died because he wasn't the person he appeared to be. He wasn't a person at all, just a void he hoped Daisy would fill.
"Owl Eyes" is seen in the library exclaiming that Gatsby was real because the books were filled with stories. He is important because he confirms to the reader that Gatsby is to make his entrance soon. He is also one of the few people who sees Gatsby as a person and not just a myth. This can also be seen when he appears at Gatsby's funeral, giving both himself and Gatsby humane qualities. You can also connect him to Eckleburg's eyes in which he sees all (all of Gatsby), and realizes that they are real.