title: A method for profiling biometric changes during disaccommodation.
abstract: OBJECTIVE
  To demonstrate the application of low-coherence reflectometry to the study of biometric changes during disaccommodation responses in human eyes after cessation of a near task and to evaluate the effect of contact lenses on low-coherence reflectometry biometric measurements.
  
  
  METHODS
  Ocular biometric parameters of crystalline lens thickness (LT) and anterior chamber depth (ACD) were measured with the LenStar device during and immediately after a 5 D accommodative task in 10 participants. In a separate trial, accommodation responses were recorded with a Shin-Nippon WAM-5500 optometer in a subset of two participants. Biometric data were interleaved to form a profile of post-task anterior segment changes. In a further experiment, the effect of soft contact lenses on LenStar measurements was evaluated in 15 participants.
  
  
  RESULTS
  In 10 adult participants, increased LT and reduced ACD was seen during the 5 D task. Post-task, during fixation of a 0 D target, a profile of the change in LT and ACD against time was observed. In the two participants with accommodation data (one a sufferer of nearwork-induced transient myopia and other a non-sufferer), the post-task changes in refraction compared favorably with the interleaved LenStar biometry data. The insertion of soft contact lenses did not have a significant effect on LenStar measures of ACD or LT (mean change: -0.007 mm, p = 0.265 and + 0.001 mm, p = 0.875, respectively).
  
  
  CONCLUSIONS
  With the addition of a relatively simple stimulus modification, the LenStar instrument can be used to produce a profile of post-task changes in LT and ACD. The spatial and temporal resolution of the system is sufficient for the investigation of nearwork-induced transient myopia from a biometric viewpoint. LenStar measurements of ACD and LT remain valid after the fitting of soft contact lenses.
authors.affiliation: Bradford School of Optometry and Vision Science, University of Bradford, Bradford, West Yorkshire, UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Alderson
authors.forename: Leon N
authors.initials: LN
authors.lastname: Davies
authors.forename: Edward A H
authors.initials: EA
authors.lastname: Mallen
authors.forename: Amy L
authors.initials: AL
authors.lastname: Sheppard
mesh_terms: D000065:Accommodation, Ocular; D000328:Adult; D000867:Anterior Chamber / Q000033:anatomy & histology*; D001699:Biometry / Q000379:methods*; D005260:Female; D006801:Humans; D007908:Lens, Crystalline / Q000033:anatomy & histology* / Q000502:physiology*; D008297:Male; D009216:Myopia / Q000175:diagnosis / Q000503:physiopathology*; D010775:Photic Stimulation; D012016:Reference Values; D012029:Refraction, Ocular; D015203:Reproducibility of Results; D014787:Vision Tests / Q000379:methods; D055815:Young Adult