title: Papua New Guinea vision-specific quality of life questionnaire: a new patient-reported outcome instrument to assess the impact of impaired vision.
abstract: BACKGROUND
  The aim of this study was to develop and validate a new vision-specific quality of life (VS QoL) instrument and to assess the impact of vision impairment and eye disease on the quality of life of adults in Papua New Guinea (PNG).
  
  
  METHODS
  This study was designed as community based cross-sectional.
  
  
  METHODS
  Six hundred fourteen adults aged 18 and above were included in this study.
  
  
  METHODS
  Focus groups and interviews guided development of a 41-item instrument. Two valid subscales of the instrument were obtained using pilot data after an iterative item reduction process guided by Rasch-based parameters. The person measures (in logits) of 614 participants were used to assess quality of life using univariate and multivariate regression analysis.
  
  
  METHODS
  Rasch logits.
  
  
  RESULTS
  Rasch analysis confirmed a 17-item instrument containing an 8-item activity limitation subscale and a 9-item well-being subscale. Both subscales were unidimensional and demonstrated good fit statistics, measurement precisions and absence of significant differential item functioning. A consistent deterioration in vision-specific quality of life was independently and significantly associated with levels of vision. Severity of vision impairment and ocular morbidity were independently associated with activity limitation and emotional well-being. Participants with refractive error had lower quality of life score than those with no ocular abnormality but higher score than those with cataract and other eye diseases.
  
  
  CONCLUSIONS
  The 17-item PNG-VS QoL instrument is a valid and reliable instrument for the assessment of impact of impaired vision on quality of life in PNG. Vision-specific quality of life was significantly worse among participants who were older and less-educated, had lower income and have had ocular morbidities.
authors.affiliation: Brien Holden Vision Institute, Sydney, New South Wales, Australia.
authors.forename: Prakash
authors.initials: P
authors.lastname: Paudel
authors.forename: Jyoti
authors.initials: J
authors.lastname: Khadka
authors.forename: Anthea
authors.initials: A
authors.lastname: Burnett
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Hani
authors.forename: Thomas
authors.initials: T
authors.lastname: Naduvilath
authors.forename: Tim R
authors.initials: TR
authors.lastname: Fricke
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004522:Educational Status; D005128:Eye Diseases / Q000453:epidemiology / Q000523:psychology*; D005260:Female; D006801:Humans; D007182:Income; D008297:Male; D008875:Middle Aged; D010219:Papua New Guinea / Q000453:epidemiology; D010865:Pilot Projects; D011594:Psychometrics; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D018434:Sickness Impact Profile; D011795:Surveys and Questionnaires; D014785:Vision, Ocular; D019987:Persons with Visual Disabilities / Q000523:psychology*
keywords: Rasch analysis; impaired vision; quality of life; questionnaire