Dinkin Dings and the Double From Dimension 9

What's the book about?

A very nervous boy is told he has to start wearing glasses, and he’s sure they’re going to cause all sorts of trouble. When he tries to get rid of them, he accidentally brings a bold, fearless double of himself from another dimension into his world. Soon, the two boys and their monster friends must face some truly terrifying creatures and figure out how to save the day together.