Psychometric Properties of the NEI-RQL-42 Questionnaire in Keratoconus
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Date
2012-10
Authors
McAlinden, Colm
Khadka, Jyoti
Santos Paranhos, Juliane de Freitas
Schor, Paulo
Pesudovs, Konrad
Journal Title
Journal ISSN
Volume Title
Publisher
Association for Research in Vision and Ophthalmology, Inc.
Rights
Copyright 2012 The Association for Research in Vision and Ophthalmology, Inc.
Rights Holder
The Association for Research in Vision and Ophthalmology, Inc.
Abstract
Purpose.: To assess the psychometric properties of the National Eye Institute Refractive Error Quality of Life (NEI-RQL-42) questionnaire in keratoconus and compare these findings to patients with refractive error correction alone.
Methods.: The Portuguese version of the NEI-RQL-42 Quality of Life questionnaire was completed by 44 patients who had keratoconus before and after implantation of intracorneal ring segments. Rasch analysis was used to assess the use of response categories, success in measuring a single trait per subscale (unidimensionality), ability to discriminate person ability (precision), and targeting of questions to person quality of life (QoL).
Results.: Rasch analysis was performed for the questionnaire subscales using stacked preoperative and postoperative data. Three subscales (Symptoms, Dependence on correction, and Suboptimal correction) contained response categories that were not used as intended. Six subscales contained misfitting items indicating multidimensionality. Eleven subscales exhibited inadequate measurement precision. Only the Near vision subscale demonstrated adequate precision with a person separation greater than 2.0. Targeting of items to person QoL was adequate in 11 of the 12 subscales with a mean item location of less than 1 logit.
Conclusions.: Only one NEI-RQL-42 subscale (Near vision) performed adequately in keratoconus. Targeting was better in patients with keratoconus than in patients with refractive error correction alone, but 11 of the 12 subscales remain manifestly inadequate. Better instruments exist for measuring patient-reported outcomes in keratoconus.
Description
This article is made available with the permission of the publisher, Association for Research in Vision and Ophthalmology
Keywords
National Eye Institute Refractive Error Quality of Life (NEI-RQL-42), keratoconus, intracorneal ring segments, quality of life (QoL)
Citation
Colm McAlinden, Jyoti Khadka, Juliane de Freitas Santos Paranhos, Paulo Schor, Konrad Pesudovs; Psychometric Properties of the NEI-RQL-42 Questionnaire in Keratoconus. Invest. Ophthalmol. Vis. Sci. 2012;53(11):7370-7374. doi: 10.1167/iovs.12-9969.