title: Development of a near activity visual questionnaire to assess accommodating intraocular lenses.
abstract: OBJECTIVE
  To develop a questionnaire that subjectively assesses near visual function in patients with 'accommodating' intraocular lenses (IOLs).
  
  
  METHODS
  A literature search of existing vision-related quality-of-life instruments identified all questions relating to near visual tasks. Questions were combined if repeated in multiple instruments. Further relevant questions were added and item interpretation confirmed through multidisciplinary consultation and focus groups. A preliminary 19-item questionnaire was presented to 22 subjects at their 4-week visit post first eye phacoemulsification with 'accommodative' IOL implantation, and again 6 and 12 weeks post-operatively. Rasch Analysis, Frequency of Endorsement, and tests of normality (skew and kurtosis) were used to reduce the instrument. Cronbach's alpha and test-retest reliability (intraclass correlation coefficient, ICC) were determined for the final questionnaire. Construct validity was obtained by Pearson's product moment correlation (PPMC) of questionnaire scores to reading acuity (RA) and to Critical Print Size (CPS) reading speed. Criterion validity was obtained by receiver operating characteristic (ROC) curve analysis and dimensionality of the questionnaire was assessed by factor analysis.
  
  
  RESULTS
  Rasch Analysis eliminated nine items due to poor fit statistics. The final items have good separation (2.55), internal consistency (Cronbach's alpha=0.97) and test-retest reliability (ICC=0.66). PPMC of questionnaire scores with RA was 0.33, and with CPS reading speed was 0.08. Area under the ROC curve was 0.88 and Factor Analysis revealed one principal factor.
  
  
  CONCLUSIONS
  The pilot data indicates the questionnaire to be internally consistent, reliable and a valid instrument that could be useful for assessing near visual function in patients with 'accommodating' IOLS. The questionnaire will now be expanded to include other types of presbyopic correction.
authors.affiliation: Ophthalmic Research Group, School of Life and Health Sciences, Aston University, Birmingham, B4 7ET, UK.
authors.forename: Navneet
authors.initials: N
authors.lastname: Gupta
authors.forename: James S
authors.initials: JS
authors.lastname: Wolffsohn
authors.forename: Shehzad A
authors.initials: SA
authors.lastname: Naroo
authors.forename: Leon N
authors.initials: LN
authors.lastname: Davies
authors.forename: George A
authors.initials: GA
authors.lastname: Gibson
authors.forename: Sunil
authors.initials: S
authors.lastname: Shah
mesh_terms: D000065:Accommodation, Ocular; D006801:Humans; D007910:Lenses, Intraocular; D011474:Prosthesis Design; D011788:Quality of Life; D011795:Surveys and Questionnaires / Q000592:standards*; D014785:Vision, Ocular