Purpose: Most trials that study the lens movement of accommodative intraocular lens (IOLs) use pilocarpine to stimulate ciliary muscle contraction. The aim of this study is to assess in vivo whether a more physiologic, stimulus- driven accommodation is comparable to pilocarpine- induced IOL movement. Design: Controlled patient- and examiner- masked clinical trial. Participants: The study population included 38 eyes with accommodative IOL implants (1CU) and a control group of 28 eyes with conventional open- loop IOLs. Methods: A highprecision biometry technique, partial coherence interferometry, was used tomeasure IOL position. Anterior chamber depthwas measured during physiologic (near point) and pharmacological (pilocarpine 2% ) stimulation. In a subgroup of 14 1CU eyes, IOL position was determined repeatedly within 90 minutes after pilocarpine administration. A different subgroup was investigated as to the effect of cyclopentolate on IOL position. Best- corrected distance visual acuity (VA), best- corrected near VA, and distance- corrected near VA (DCNVA) were assessed using logarithm of the minimum angle of resolution charts. Main Outcome Measures: Anterior chamber depth change under pilocarpine and near- point- driven accommodation. Results: Near- point accommodation did not induce movement of either the accommodating 1CU or the control IOLs. Pilocarpine induced a 201± 0.137 mm anterior movement of the 1CU IOL (P< 0.001), compared with no movement within the control IOL groups (P >0.05). There was no significant (P >0.05) difference in DCNVA between the accommodative and open- loop IOLs. No correlation between near point- or pilocarpine- stimulated IOL movement and DCNVA was found. Concerning the time course of movement after pilocarpine administration, most of the 1CU IOLs showed somemovement 30 minutes after application. Cyclopentolate- induced ciliary muscle relaxation caused a posterior IOL movement, as compared with the relaxed state, when focusing on a distant target. Conclusion: Pilocarpine- induced ciliary muscle contraction seems to overestimate IOL movement relative to a monocular near- driven stimulus. Therefore, concerning IOL movement, pilocarpine may act as a superstimulus and may not adequately simulate daily life performance of accommodative IOLs. However, it may be helpful to evaluate the maximum potential of an accommodating IOL. Purpose: Most trials that study the lens movement of accommodative intraocular lens (IOLs) use pilocarpine to stimulate ciliary muscle contraction. The aim of this study is to assess in vivo whether comparable to a more physiologic, stimulus-driven accommodation is comparable to pilocarpine-induced IOL movement. Design: Controlled patient- and examiner-masked clinical trial. Participants: The study population included 38 eyes with accommodative IOL implants (1CU) and a control group of 28 eyes with conventional open-loop IOLs. Methods: A highprecision biometry technique, Partial coherence interferometry, was used to measure IOL position. Anterior chamber depth was measured during physiologic (near point) and pharmacological (pilocarpine 2%) stimulation. A subgroup of 14 1CU eyes, IOL position was determined repeated within 90 minutes after pilocarpine administration. A different subgroup was investigated as to the effect of cyclopentolate on IOL position. Best- corrected distance visual acui ty (VA), best-corrected near VA, and distance-corrected near VA (DCNVA) were assessed using logarithm of the minimum angle of resolution charts. Main Outcome Measures: Anterior chamber depth change under pilocarpine and near- point- driven accommodation. Pilocarpine induced a 201 ± 0.137 mm anterior movement of the 1CU IOL (P <0.001), compared with no movement within the control IOL groups (P > 0.05). There was no significant (P> 0.05) difference in DCNVA between the accommodative and open-loop IOLs. No correlation between near point- or pilocarpine-stimulated IOL movement and DCNVA was found. Concerning the time course of movement after pilocarpine administration, most of the 1CU IOLs showed some movement 30 minutes after application. Cyclopentolate-induced ciliary muscle relaxation caused a posterior IOL movement, as compared with the relaxed state, when focusing on a di sConclusion: Pilocarpine-induced ciliary muscle contraction seems to overestimate IOL movement relative to a monocular near-driven stimulus. Thus, concerning IOL movement, pilocarpine may act as a superstimulus and may not adequately simulate daily life performance of accommodative IOLs. However, , it may be helpful to evaluate the maximum potential of an accommodating IOL.