title: Successful monovision contact lens wearers refitted with bifocal contact lenses.
abstract: OBJECTIVE
  Should successful monovision contact lens wearers be refitted with bifocal lenses?
  
  
  METHODS
  Fifty current monovision lens wearers were fitted with ACUVUE Bifocal contact lenses (Johnson & Johnson Vision Care, Jacksonville, FL). Visual function and subjective vision ratings were assessed with habitual monovision lenses at the first visit and then were repeated at the end of 6 months while wearing bifocal lenses. Lens preference was determined at the end of the 6-month study, and the subjects were called 1 year later to repeat the lens preference questionnaire.
  
  
  RESULTS
  Forty (80%) subjects completed the 6-month study; nine discontinued for visual reasons. At the end of 6 months of wear, 68% preferred bifocal lenses and 25% preferred monovision. Of the subjects who were contacted a year later, 53% were still wearing bifocal lenses. High-contrast visual acuity and letter contrast sensitivity at distance was the same for monovision and bifocal lenses, but low-contrast acuity was better with monovision. Intermediate low- and high-contrast acuity and 3-meter and near stereoscopic acuity were better with bifocal lenses. Near high- and low-contrast acuity were better with monovision. All subjective ratings, except near vision in poor lighting, were significantly greater with bifocal lenses.
  
  
  CONCLUSIONS
  It is possible to refit successful monovision lens wearers with simultaneous vision bifocal lenses, and these lenses should be considered as an alternative method for the correction of presbyopia. In addition, subjective responses to bifocal lenses may not be reflective of visual function measurements.
authors.affiliation: Centre ofr Contact Lens Research, University of Waterloo, Waterloo, Ontario, Canada. psitu@uwaterloo.ca
authors.forename: Ping
authors.initials: P
authors.lastname: Situ
authors.forename: Rènée
authors.initials: R
authors.lastname: Du Toit
authors.forename: Desmond
authors.initials: D
authors.lastname: Fonn
authors.forename: Trefford
authors.initials: T
authors.lastname: Simpson
mesh_terms: D000328:Adult; D000368:Aged; D003263:Contact Lenses, Hydrophilic; D015350:Contrast Sensitivity / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D017060:Patient Satisfaction; D011305:Presbyopia / Q000628:therapy*; D011446:Prospective Studies; D017755:Prosthesis Fitting; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology