title: Development and validation of a vision and night driving questionnaire.
abstract: Night-time driving difficulties are a common concern of older drivers and those with eye disease. This study aimed to develop and validate a questionnaire for assessing vision-related night driving difficulties in older drivers.
  
  
  
  Items from existing vision-related quality of life questionnaires and driving studies were used to develop a questionnaire that was completed by 283 participants who reported visual difficulties for night driving (65% female, 50 to >80 years). The questionnaire included items relating to demographic and night driving characteristics (seven items), general vision ratings (eight items), vision-related night driving difficulties (11 items), and a single open question about specific night driving difficulties. The vision-related night driving difficulty items were analysed separately using Rasch analysis to form the vision and night driving questionnaire (VND-Q). Rasch analysis assessed validity and psychometric properties of the scale. Generalised linear regression models examined associations between VND-Q scores and age, gender, amount of night driving, self-rated vision, and eye conditions. Test-retest repeatability was assessed using intra-class correlation analysis and Bland-Altman methods of agreement for a subset of 30 participants.
  
  
  
  Rasch analysis indicated that a nine-item VND-Q scale was unidimensional, valid and reliable, and showed excellent discriminant ability (person separation index 3.04; person reliability 0.90). Targeting was better for those with greater self-reported night driving difficulties. Participants with self-reported bilateral eye conditions and worse self-reported general vision ratings had significantly more night driving difficulties with the VND-Q scale than individuals without eye conditions (p = 0.03) and with better general vision ratings (p < 0.001). Females reported more difficulties than males (p < 0.001) and drove shorter distances at night per week which was also associated with greater difficulties (p < 0.001). A repeatability coefficient (Rc ) of 2.07 demonstrated excellent test-retest repeatability.
  
  
  
  The nine-item VND-Q is a unidimensional and reliable questionnaire allowing quantification of the level of visual difficulties that older drivers report at night. The development of this questionnaire is an important step in providing a reliable and validated instrument for use to guide appropriate investigations, referrals, or interventions in clinical and research settings.
authors.affiliation: School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Janessa A
authors.initials: JA
authors.lastname: Kimlin
authors.affiliation: School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Alex A
authors.initials: AA
authors.lastname: Black
authors.affiliation: School of Public Health, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Ngadiman
authors.initials: N
authors.lastname: Djaja
authors.affiliation: School of Optometry and Vision Science, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Wood
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001334:Automobile Driving / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D055254:Night Vision / Q000502:physiology*; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D014792:Visual Acuity
keywords: Rasch analysis; night-driving; patient-reported outcomes; questionnaire; vision