The character known only as Owl Eyes is a minor character in The Great Gatsby by F. Scott Fitzgerald; however, he gives us some valuable information about who Jay Gatsby is.'
We first meet Owl Eyes (so named because he is wearing glasses) at one of Gatsby's parties, though of course his presence there does not necessarily imply any connection between him and Gatsby. He is in the library and is quite drunk, but he is mostly surprised at a discovery he has made. All of the books are perfectly real; however, they have not been cut.
"See!" he cried triumphantly. "It's a bona-fide piece of printed matter. It fooled me. This fella's a regular Belasco. It's a triumph. What thoroughness! What realism! Knew when to stop, too--didn't cut the pages. But what do you want? What do you expect?"
The books being uncut refers to the practice of printing books with pages that are still connected at the top or bottom; when one wanted to read these books, then, he had to use a knife or something like a letter opener to cut the pages.
What these uncut books indicate, of course, is that Jay Gatsby has all the trappings of wealth and class but is an impostor. Like the books, he is real but not he is not educated as he claims to be. He has procured the books, but he knows he does not have to read them to be seen as the person he wants people to think he is. The books are not fakes, but they are not what they seem to be, just like their owner.
At the end of that same party, the inebriated owl-eyed man is part of a rather outrageous drunken car accident, though he admits that he is not the driver. Of course this is a kind of foreshadowing of things to come.
At the end of the story, Owl Eyes is one of the only people who attends Gatsby's funeral; even more, he expresses some sense of sympathy for Gatsby's death:
Owl-eyes spoke to [Nick] by the gate.
"I couldn't get to the house," he remarked.
"Neither could anybody else."
"Go on!" He started. "Why, my God! They used to go there by the hundreds." He took off his glasses and wiped them again, outside and in.
"The poor son-of-a-bitch," he said.
We do not know much of anything about Owl Eyes outside of these incidents, and that certainly suggests that the other aspects of his character are unimportant or Fitzgerald would have included those details. Instead, the author makes sure we get this detail: Owl Eyes is constantly rubbing his glasses in order to see more clearly. Given what he "sees" in Gatsby, he helps us understand Gatsby more clearly, as well.