title: Anterior chamber depth measurements in eyes with an accommodating intraocular lens: agreement between partial coherence interferometry and optical coherence tomography.
abstract: OBJECTIVE
  To determine agreement between partial coherence interferometry (PCI) and anterior segment optical coherence tomography (AS-OCT) measurements of anterior chamber depth (ACD) and axial intraocular lens (IOL) movement in eyes with an accommodating IOL.
  
  
  METHODS
  Department of Ophthalmology, St. Thomas' Hospital, London, United Kingdom.
  
  
  METHODS
  In this prospective pilot study of cataract patients, the central ACD was measured by PCI (ACMaster) and AS-OCT (Visante) 6 months after unilateral OPAL-A accommodating IOL implantation. Measurements were performed with a distance target and 1.00 diopter (D) and 2.00 D accommodative targets and after administration of topical pilocarpine 4%. Agreement between PCI and AS-OCT ACD measurements and IOL movement was calculated.
  
  
  RESULTS
  Measurements were obtained in 18 patients. There was a consistent and statistically significant bias toward shallower ACD measurements with AS-OCT than with PCI, with the bias most pronounced after pilocarpine (mean 4.117 mm +/- 0.291 [SD] versus 4.054 +/- 0.287 mm; bias 0.063 mm; P<.0001). Limited IOL movement to 1.00 D and 2.00 D accommodative stimuli was detected with both instruments. After pilocarpine, forward IOL movement measurements were statistically significantly greater by AS-OCT than by PCI (mean 0.306 +/- 0.161 mm versus 0.270 +/- 0.155 mm) (P = .017).
  
  
  CONCLUSIONS
  The AS-OCT device showed a bias toward underestimation of ACD compared with the PCI device. The bias increased as ACD shallowed with pilocarpine, resulting in overestimation of forward IOL movement by AS-OCT. This may lead to overestimation of the accommodative performance of IOLs. The ACD measurements obtained by the 2 devices are not interchangeable.
authors.affiliation: Department of Ophthalmology, St. Thomas' Hospital, Kings College, London, United Kingdom.
authors.forename: Georgia
authors.initials: G
authors.lastname: Cleary
authors.forename: David J
authors.initials: DJ
authors.lastname: Spalton
authors.forename: John
authors.initials: J
authors.lastname: Marshall
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000867:Anterior Chamber / Q000473:pathology*; D000886:Anthropometry; D005260:Female; D006801:Humans; D007368:Interferometry; D007910:Lenses, Intraocular; D008027:Light; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology