Misajon Roseanne, Hawthorne Graeme, Richardson Jeff, Barton Jodi, Peacock Stuart, Iezzi Angelo, Keeffe Jill
Department of Ophthalmology, University of Melbourne, Australia.
Invest Ophthalmol Vis Sci. 2005 Nov;46(11):4007-15. doi: 10.1167/iovs.04-1389.
To identify the content for a vision and quality of life-related utility measure (Vision Quality of Life Index [VisQoL]) for the economic evaluation of eye care and rehabilitation programs.
Focus groups of the visually impaired elicited key concepts. Based on these and previous research, 33 items were generated. These were administered to visually impaired adults (n = 70) and a representative sample of unimpaired adults (n = 86). The item bank was reduced through examination of item properties, exploratory factor (EFA), item response theory (IRT), and structural equation modeling (SEM) analyses. The resultant model was confirmed through administration to a second sample of participants.
Focus group themes included physical well-being, social well-being, independence, self-actualization, emotional well-being, and planning and organization. Poorly performing items were eliminated on basic psychometric properties, including failure to discriminate. Next, EFA loadings were used to select items. Twelve items survived. To minimize redundancy, IRT analysis and SEM reduced the VisQoL item pool to six items (Cronbach alpha = 0.88). To confirm this model, these items were then administered to an additional 218 participants; 35% with a vision impairment. A pooled SEM analysis showed the model to have very good fit properties (root mean square error of approximation [RMSEA] = 0.000). A preliminary test of the model against visual acuity showed a significant monotonic relationship.
The short 6-item VisQoL has excellent psychometric properties as a simple summative instrument. It can be used in its present state as a condition-specific outcome measure for the evaluation of healthcare interventions for the visually impaired. The descriptive model is also suitable for generating utility values for the economic evaluation of vision-related programs and services.
确定用于眼科护理和康复项目经济评估的、与视力和生活质量相关的效用测量指标（视力生活质量指数[VisQoL]）的内容。
通过视障者焦点小组确定关键概念。基于这些概念和先前的研究，生成了33个条目。将这些条目施测于成年视障者（n = 70）和无视力障碍的成年代表性样本（n = 86）。通过检查条目属性、探索性因子分析（EFA）、项目反应理论（IRT）和结构方程模型（SEM）分析来减少条目库。通过对第二批参与者样本进行施测来验证所得模型。
焦点小组的主题包括身体健康、社会福祉、独立性、自我实现、情绪健康以及规划和组织。根据基本心理测量属性（包括无法区分）淘汰表现不佳的条目。接下来，使用EFA载荷来选择条目。12个条目保留下来。为了尽量减少冗余，IRT分析和SEM将VisQoL条目库减少到6个条目（克朗巴哈α系数 = 0.88）。为了验证该模型，随后将这些条目施测于另外218名参与者；其中35%有视力障碍。汇总的SEM分析表明该模型具有非常好的拟合特性（近似均方根误差[RMSEA] = 0.000）。该模型与视力的初步测试显示出显著的单调关系。
简短的6条目VisQoL作为一种简单的汇总工具具有出色的心理测量特性。它可以直接用于作为特定条件下的结果测量指标，以评估针对视障者的医疗保健干预措施。该描述性模型也适用于为与视力相关的项目和服务的经济评估生成效用值。
