title: Effect of accommodation and pupil size on the movement of a posterior chamber lens in the phakic eye.
abstract: OBJECTIVE
  Although a posterior chamber phakic intraocular lens provides effective refractive correction of high myopia and hyperopia, mechanical contact between the implantable contact lens (ICL) and the crystalline lens and inadequate aqueous circulation in the prelenticular space could cause subcapsular opacification. To assess whether and to what extent such mechanical contact occurs, changes in the distance between the STAAR Collamer ICL and the crystalline lens under various conditions were investigated.
  
  
  METHODS
  Open pilot study.
  
  
  METHODS
  Thirteen eyes of 11 myopic and 2 hyperopic patients with a mean age of 38 years (range, 19-53 years) were examined at least 6 months after ICL implantation.
  
  
  METHODS
  A noninvasive, high-resolution biometry technique, partial coherence interferometry, was used to measure distance changes between the ICL and the crystalline lens during subjective accommodation, after instillation of pilocarpine, and under changing light conditions.
  
  
  METHODS
  Mean distance changes from the posterior corneal surface to the ICL, from the posterior corneal surface to the anterior surface of the crystalline lens, and the distance between the ICL and the crystalline lens.
  
  
  RESULTS
  In the nonaccommodated state, the mean distance between the ICL and the crystalline lens was 457 microm (range, 123-924 microm). During subjective accommodation, a significant (P<0.01) decrease and, after topical application of pilocarpine, a nonsignificant (P=0.35) decrease of anterior chamber depth was accompanied by a nonsignificant (P = 0.71) reduction of the ICL-crystalline lens distance. Under photopic conditions, a significant mean reduction (P<0.01) of the ICL-crystalline lens distance of -28 microm (range, -16 to -188 microm) was observed.
  
  
  CONCLUSIONS
  Partial coherence interferometry biometry enabled noninvasive high-precision investigation of ICL dynamics. No significant changes between the ICL and the crystalline lens were detected during subjective accommodation and after application of pilocarpine. However, under photopic conditions, with constriction of the pupil, the distance between the ICL and the crystalline lens was significantly reduced. This mechanism might cause inadequate aqueous circulation in the prelenticular space and might be one of the causes of subcapsular opacification in some of the eyes after ICL implantation.
authors.affiliation: Department of Ophthalmology, University of Vienna, Vienna, Austria.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Petternel
authors.forename: Christina-Maria
authors.initials: CM
authors.lastname: Köppl
authors.forename: Irene
authors.initials: I
authors.lastname: Dejaco-Ruhswurm
authors.forename: Oliver
authors.initials: O
authors.lastname: Findl
authors.forename: Christian
authors.initials: C
authors.lastname: Skorpik
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Drexler
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D001699:Biometry; D002924:Ciliary Body / Q000187:drug effects; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000601:surgery; D007368:Interferometry; D007498:Iris / Q000187:drug effects; D019654:Lens Implantation, Intraocular; D007908:Lens, Crystalline / Q000502:physiology*; D007910:Lenses, Intraocular; D008027:Light; D008297:Male; D008875:Middle Aged; D008916:Miotics / Q000008:administration & dosage; D009068:Movement; D009216:Myopia / Q000601:surgery; D010862:Pilocarpine / Q000008:administration & dosage; D011680:Pupil / Q000502:physiology*
chemical_list: D008916:Miotics; D010862:Pilocarpine