。
The editor glanced through the manuscript.
Literal
Editor [topic-は] manuscript [through-に] quickly eye [object-を] passed.
目を通す literally means 'to pass one's eyes through' — an idiom for skimming or reading through a document. さっと is a 擬態語 for swift, efficient motion, modifying how the editor read: not carefully, but with a quick professional once-over.