Cyclopentolate is an antagonist of muscarinic acetylcholine receptors (Kis = 1.62, 27.5, and 2.63 nM for M1, M2, and M3 receptors, respectively). It inhibits carbachol-induced contraction of isolated human iris sphincter, circular ciliary muscle, and longitudinal ciliary muscle (Kbs = 7.9, 15.8, and 12.5 nM, respectively). Formulations containing cyclopentolate have been used to induce pupil dilation and to prevent the eye from accommodating for near vision.