title: Changes in accommodative responses with multifocal contact lenses: a pilot study.
abstract: OBJECTIVE
  To evaluate induced changes in pupil and accommodative response for different accommodative stimuli with three different multifocal contact lenses (CLs).
  
  
  METHODS
  Accommodative and pupil responses with three aspheric multifocal CLs of simultaneous focus center near (PureVision Low Add, PureVision High Add and Focus Progressives) for two accommodative stimuli of -2.5 and -4.00 D were recorded in 10 young subjects. Accommodative response, peak velocity, and time constant of accommodation and pupil constriction were assessed. The measurements were evaluated in all the participants with distance-single vision CLs and with the three multifocal CLs. The monocular measurements were performed in a random sequence for each participant. All parameters were measured with a Hartmann-Shack aberrometer (IRX-3; Imagine Eyes, Orsay, France).
  
  
  RESULTS
  Differences were not found in accommodation response for both accommodative stimuli studied between the single vision lens and the three different multifocal CLs (p > 0.05 for both stimuli). For the 2.5 D stimulus, significant differences were not found in peak velocity and time constant between the single vision lens and the three different multifocal CLs (p > 0.05 for all situations); in amplitude of pupil constriction, differences were only found for the situation with PureVision High Add, where the value was lower than the single vision lens (p = 0.015). For the 4.00 D stimulus, differences with single vision lens in peak of velocity and time constant were only found with PureVision Low Add, where the peak velocity value was higher and the time constant was lower (p = 0.024 and p = 0.032 for peak of velocity and time constant, respectively); for amplitude of pupil constriction differences were not found (p > 0.05).
  
  
  CONCLUSIONS
  Data obtained in this pilot study suggest that in young observers, the multifocal CLs studied do not induce large changes in accommodative system compared with the single vision lens.
authors.affiliation: Optometry Research Group, Optics Department, University of Valencia, Valencia, Spain. davidmadridcosta@hotmail.com
authors.forename: David
authors.initials: D
authors.lastname: Madrid-Costa
authors.forename: Javier
authors.initials: J
authors.lastname: Ruiz-Alcocer
authors.forename: Hema
authors.initials: H
authors.lastname: Radhakrishnan
authors.forename: Teresa
authors.initials: T
authors.lastname: Ferrer-Blasco
authors.forename: Robert
authors.initials: R
authors.lastname: Montés-Micó
mesh_terms: D000065:Accommodation, Ocular / Q000502:physiology*; D000328:Adult; D003261:Contact Lenses; D018592:Cross-Over Studies; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D010865:Pilot Projects; D011680:Pupil / Q000502:physiology*; D012029:Refraction, Ocular / Q000502:physiology*; D012030:Refractive Errors / Q000503:physiopathology / Q000628:therapy*; D016896:Treatment Outcome; D014792:Visual Acuity