Does acetylcholine have anything to do with how vision works?

Yes, in a way.: Acetylcholine transmits signals from nerves to muscles, such as those that control the pupil size and the focusing power. When these muscles are activated, the pupil will get smaller and the focusing muscles will contract, enabling the eye to see up close, as for reading. These two actions can also normally occur separately. Acetylcholine is sometimes used during eye surgery.