A very short version of the Visual Function Questionnaire (VFQ-3oo7) for use as a routinely applied Patient-Reported Outcome Measure

Abstract

Background: Patient-reported outcome measures (PROMs) are valuable supplements in regular care to facilitate routine monitoring of quality of life from the patient’s perspective. The 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25) is a widely used PROM in ophthalmology. However, the NEI-VFQ-25 is too time-consuming and cumbersome for routine evaluations in regular care. The aim of this study is to construct a 7-item questionnaire of which only 3 items are presented to the patient, by means of routing. This VFQ 3 out of 7 (VFQ-3oo7) should have a minimal loss of information compared with the NEI-VFQ-25. Methods: An historical database including 3293 administrations of the NEI-VFQ-25 was constructed involving patients with retinal detachment, cataract, corneal diseases, glaucoma, macular degeneration, uveal melanoma and a normal population sample. The data were subjected to Rasch analyses, in particular a generalized partial credit model. Items were sorted on the latent trait and divided into seven categories. From each category, the item with the highest discriminative value was selected. Through routing, only three out of the seven remaining questions are used, where the answers navigate patients to a fitting trait level. Results: A one-dimensional structure was considered fitting. The VFQ-3oo7 showed a small loss of information compared with the total score of the NEI-VFQ-25: correlation 0.927 and a relative precision of 0.868. Conclusion: The very short, but valid, VFQ-3oo7 can be applied to evaluate the patient's perceived vision-related health status in routine evaluations of treatments in regular care, with a small burden for patients.