One of the best ways to keep readers engaged in a story is to give them an eyeball kick. A term coined by science fiction writer Rudy Rucker, an eyeball kick is “a perfect, telling detail that creates an instant and powerful visual image,” according to the Science Fiction Writers of America.

Consider this example an of eyeball kick (I’ve intentionally boldfaced it.) from the novel “Quantum: Event Horizon” by Zac McNabb, in which the foster parent Ron speaks of his two children:

“It’s alright. The Lord has blessed her with good judgment. I believe the Lord has blessed Samuel with the wisdom needed to keep family secrets. Luke 8:10 says ‘The knowledge of the secrets of the kingdom of God has been given to you. But to others I speak in parables, so that, though seeing, they may not see; Though hearing, they may not understand.’” Ron picks the raw meat out of his teeth. “That means God wants you to honor your families, and it’s ok keep secrets, because others may not understand.”

What makes an instant and powerful image? First, it must be evocative, meaning it brings out strong emotions or feelings in readers. Ron picks the raw meat out of his teeth accomplishes this by rousing a sense of revulsion in the reader. In addition, the image adds to the story’s meaning by providing a new layer of understanding or an insight into it. The reader suddenly knows that Ron is a child abuser of some sort. In this way, the image creates instant understanding.

Be careful of overdoing it, though. An image that tries too hard to be evocative can misfire, undercutting the story. Delivering an eyeball kick requires a precise aim.