Rasch Analysis of the Quality of Life and Vision Function Questionnaire
Rasch Analysis of the Quality of Life and Vision Function Questionnaire
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DOI：
10.1097/opx.0b013e3181ae1ec7
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发表时间：
2009-07-01
影响因子：
1.4
通讯作者：
Pesudovs, Konrad
中科院分区：
文献类型：
--
作者：
Gothwal, Vijaya K.;Wright, Thomas A.;Pesudovs, Konrad
目的。采用经典检验理论编制生活质量和视力功能问卷（QOL-VFQ）评估白内障手术的疗效。本研究的目的是在白内障人群中使用Rasch分析来检验该问卷的心理测量特性。对389例等待白内障手术的患者自行实施17项QOL-VFQ量表。评估QOL-VFQ及其五个分量表是否符合Rasch模型。使用Rasch分析从QOL-VFQ及其五个分量表的序数得分估计“视觉能力”的间隔水平测量。评估量表的单维性、项目契合度、反应类别表现及项目对患者的针对性。QOL-VFQ及其五个分量表呈现有序的类别阈值。尽管删除了两个不匹配的项目，但人的分离信度较高，QOL-VFQ可以区分三个层次的患者能力。然而，由于大多数患者的视觉功能水平较高，因此患者对项目困难的能力的目标并不理想。没有一个分量表显示出可接受的心理测量特性。这些结果支持白内障患者QOL-VFQ整体功能良好。然而，增加更多的项目，以适应更有能力的患者，包括那些正在等待白内障手术的患者，将有助于提高目标。（光学视觉科学2009；86:836-844）
Purpose. The Quality of life and Vision Function Questionnaire (QOL-VFQ) was developed using classical test theory to assess outcomes of cataract surgery. The aim of this study was to examine the psychometric properties of this questionnaire using Rasch analysis in a cataract population.Methods. The 17-item QOL-VFQ was self-administered to 389 patients waiting to undergo cataract surgery. The QOL-VFQ and its five subscales were assessed for fit to the Rasch model. Rasch analysis was used to estimate interval level measures of "visual ability" from ordinal scores for the QOL-VFQ and its five subscales. Unidimensionality, item fit, response category performance, and targeting of items to patients were assessed.Results. The QOL-VFQ and its five subscales showed ordered category thresholds. Despite removal of two misfitting items the person separation reliability was high and the QOL-VFQ could distinguish among three strata of patient ability. However, there was suboptimal targeting of patient ability to item difficulty as most of the patients had higher levels of visual functioning. None of the subscales demonstrated acceptable psychometric properties.Conclusions. These results support the good overall functioning of the QOL-VFQ in patients with cataract. However, adding more items, that suit the more able patients including those who are awaiting cataract surgery in the fellow eye, will help improve the targeting. (Optom Vis Sci 2009;86:836-844)