Ryan Barbara, Court Helen, Margrain Tom H
School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom.
Optom Vis Sci. 2008 Feb;85(2):112-21. doi: 10.1097/OPX.0b013e31816225dc.
To describe a short, functional visual disability instrument capable of measuring the outcomes of a government funded country-wide multicenter low vision service in Wales and to determine if postal implementation might lead to response bias.
Seven items from the National Eye Institute Visual Function Questionnaire (NEI VFQ), which have previously been shown to be responsive to low vision service intervention, were incorporated into a postal questionnaire which was given to patients before they attended the all Wales Low Vision Service. Rasch analysis was used to describe the instrument's psychometric properties.
Rasch analysis of 490 completed questionnaires showed that all seven questions worked together to form a unidimensional scale. By combining the first two response categories, category utilization and targeting was improved. There were no significant differences in the age (p = 0.29), gender (p = 0.75), distance binocular Visual Acuity (VA; p = 0.86), living situation (p = 0.34) or prevalence of macular degeneration (p = 0.31) between those who returned a completed questionnaire and those who did not.
The seven-item National Eye Institute Visual Function Questionnaire is an appropriate and precise outcome measure that is acceptable to patients and easy to administer. It measures aspects of near, reading, and distance visual disability that have been shown to be amenable to low vision service provision and, therefore, it should be highly responsive to this intervention and facilitate inter-service assessment. We found no evidence to suggest that postal implementation results in response bias. The instrument is an appropriate measure of patient based outcomes for a large-scale, multicenter low vision service.
描述一种简短的功能性视觉障碍测量工具，该工具能够衡量威尔士一项由政府资助的全国多中心低视力服务的成果，并确定邮寄方式实施该工具是否会导致应答偏倚。
将美国国立眼科研究所视觉功能问卷（NEI VFQ）中的七个项目纳入一份邮寄问卷中，这七个项目先前已被证明对低视力服务干预有反应。这些项目在患者参加全威尔士低视力服务之前发放给他们。采用拉施分析来描述该工具的心理测量特性。
对490份完整问卷的拉施分析表明，所有七个问题共同构成一个单维量表。通过合并前两个应答类别，类别利用率和针对性得到了改善。完成问卷的患者与未完成问卷的患者在年龄（p = 0.29）、性别（p = 0.75）、双眼远视力（VA；p = 0.86）、生活状况（p = 0.34）或黄斑变性患病率（p = 0.31）方面没有显著差异。
七项美国国立眼科研究所视觉功能问卷是一种合适且精确的结果测量工具，患者可以接受且易于实施。它测量了近距离、阅读和远距离视觉障碍的各个方面，这些方面已被证明适合提供低视力服务，因此，它对这种干预应该有高度的反应性，并有助于服务间的评估。我们没有发现证据表明邮寄方式实施会导致应答偏倚。该工具是大规模多中心低视力服务基于患者的结果的合适测量方法。
