Ans. is 'a' i.e rest to ciliary muscles Kanski writes: 3 main indications of mydriatics in uveitisTo give comfort by relieving spasm of the ciliary muscles and sphincter of the pupil which occurs in severe acute anterior uveitis.To prevent the formation of posterior synechiae by using a short-acting mydriatic which keeps the pupil mobile ( Note that atropine is not a short-acting mydriatic )To break down synechiae.By reading these indications it appears that the primary objective of atropine is to give rest to ciliary muscles. Moreover to prevent posterior synechiae formation a short-acting mydriatic is used which keeps the pupil mobile. A long-acting mydriatic like atropine can keep pupils dilated for long durations and posterior synechiae can form in the dilated position.