Stimulus-driven versus pilocarpine-induced biometric changes in pseudophakic eyes

Ophthalmology. 2005 Mar;112(3):453-9. doi: 10.1016/j.ophtha.2004.09.021.


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 high-precision 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. 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 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 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.

Publication types

  • Clinical Trial
  • Controlled Clinical Trial

MeSH terms

  • Accommodation, Ocular / physiology*
  • Aged
  • Aged, 80 and over
  • Biometry / methods
  • Capsulorhexis
  • Ciliary Body / drug effects
  • Cyclopentolate / pharmacology
  • Double-Blind Method
  • Humans
  • Interferometry / methods
  • Lenses, Intraocular*
  • Middle Aged
  • Miotics / pharmacology*
  • Muscle Contraction / physiology*
  • Muscle, Smooth / drug effects
  • Mydriatics / pharmacology
  • Phacoemulsification
  • Pilocarpine / pharmacology*
  • Pseudophakia / physiopathology*
  • Visual Acuity / physiology


  • Miotics
  • Mydriatics
  • Pilocarpine
  • Cyclopentolate