Dougherty Bradley E, Bullimore Mark A
Ohio State University, College of Optometry, Columbus, Ohio 43210, USA.
Optom Vis Sci. 2010 Aug;87(8):543-8. doi: 10.1097/OPX.0b013e3181e61bd8.
The aim of this study was to evaluate different approaches to scoring the National Eye Institute Visual Functioning Questionnaire-25 (NEI VFQ-25) in patients with low vision including scoring by the standard method, by Rasch analysis, and by use of an algorithm created by Massof to approximate Rasch person measure. Subscale validity and use of a 7-item short form instrument proposed by Ryan et al. were also investigated.
NEI VFQ-25 data from 50 patients with low vision were analyzed using the standard method of summing Likert-type scores and calculating an overall average, Rasch analysis using Winsteps software, and the Massof algorithm in Excel. Correlations between scores were calculated. Rasch person separation reliability and other indicators were calculated to determine the validity of the subscales and of the 7-item instrument.
Scores calculated using all three methods were highly correlated, but evidence of floor and ceiling effects was found with the standard scoring method. None of the subscales investigated proved valid. The 7-item instrument showed acceptable person separation reliability and good targeting and item performance.
Although standard scores and Rasch scores are highly correlated, Rasch analysis has the advantages of eliminating floor and ceiling effects and producing interval-scaled data. The Massof algorithm for approximation of the Rasch person measure performed well in this group of low-vision patients. The validity of the subscales VFQ-25 should be reconsidered.
本研究的目的是评估在低视力患者中对美国国立眼科研究所视觉功能问卷25项版本（NEI VFQ - 25）进行评分的不同方法，包括采用标准方法评分、通过拉施分析评分以及使用马索夫创建的算法来近似拉施个人测量值。还研究了子量表的效度以及瑞安等人提出的7项简版工具的使用情况。
使用李克特式评分求和并计算总体平均值的标准方法、使用Winsteps软件进行拉施分析以及在Excel中使用马索夫算法，对50名低视力患者的NEI VFQ - 25数据进行分析。计算评分之间的相关性。计算拉施个人分离信度和其他指标，以确定子量表和7项工具的效度。
使用所有三种方法计算的评分高度相关，但标准评分方法存在地板效应和天花板效应的证据。所研究的子量表均未证明有效。7项工具显示出可接受的个人分离信度以及良好的针对性和项目性能。
尽管标准评分和拉施评分高度相关，但拉施分析具有消除地板效应和天花板效应以及生成等距量表数据的优点。用于近似拉施个人测量值的马索夫算法在这组低视力患者中表现良好。应重新考虑VFQ - 25子量表的效度。
