title: Utility of EQ-5D to assess patients undergoing cataract surgery.
abstract: OBJECTIVE
  To assess the construct validity and responsiveness of the EuroQoL-5D (EQ-5D) instrument in Asian patients undergoing cataract surgery in Singapore.
  
  
  METHODS
  In this prospective study, English- or Chinese-speaking patients (n = 216) completed the EQ-5D and the VF-14 questionnaires before and 3 months after they underwent cataract surgery. The impact of cataracts on patients was assessed using two standard gamble (SG) questions before surgery. Construct validity of the EQ-5D index and the visual analog scale (VAS) was assessed by examining their correlation with the VF-14 and SG scores. Responsiveness of the EQ-5D was compared with that of the VF-14 in terms of the magnitude of score change associated with cataract surgery.
  
  
  RESULTS
  We found that the EQ-5D index correlated with VF-14, SG (death), and SG (blindness) (Pearson r = 0.30, 0.23 and 0.24, respectively; p < 0.01). In contrast, we found no correlation between the EQ-VAS, VF-14, and SG scores. The mean EQ-5D index (difference, 0.06; effect size, 0.35) and VF-14 score (difference, 1.75; effect size, 0.97) of patients improved after cataract surgery (p < 0.0001).
  
  
  CONCLUSIONS
  Our study demonstrated that the EQ-5D utility index is a valid and responsive outcome measure for evaluating the impact of cataract surgery in our Asian population. However, the implications of using the generic EQ-5D instrument to assess the cost-effectiveness of surgical interventions for visual impairment require further investigation.
authors.affiliation: Singapore National Eye Centre, Singapore, Singapore.
authors.forename: Marcus
authors.initials: M
authors.lastname: Ang
authors.forename: Eva
authors.initials: E
authors.lastname: Fenwick
authors.forename: Tien Yin
authors.initials: TY
authors.lastname: Wong
authors.forename: Ecosse
authors.initials: E
authors.lastname: Lamoureux
authors.forename: Nan
authors.initials: N
authors.lastname: Luo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D002387:Cataract Extraction / Q000523:psychology*; D003362:Cost-Benefit Analysis; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011594:Psychometrics / Q000295:instrumentation; D011787:Quality of Health Care; D011788:Quality of Life / Q000523:psychology*; D019057:Quality-Adjusted Life Years; D018434:Sickness Impact Profile; D012846:Singapore; D011795:Surveys and Questionnaires