"Floaters" are bits of debris in the eye that resemble hairs when they enter the field of vision. They don't hurt, but can be quite the nuisance: when I am at the beach, I frequently mistake eye-floaters for sand fleas.
When one looks up or across the floaters 'jump' to that side of the field of vision, then slowly 'float' down to the bottom. The more violently one looks around, the more quickly they race around the field of vision, like cats chasing a mouse.
Sin is sort of like floaters. No sooner do we look toward God than the sin-floaters race around to compete for our attention. Believers, then, should be constantly repenting, constantly turning away from sin (floaters) and constantly turning our gaze toward God.