Mangione CM, Lee PP, Gutierrez PR, Spritzer K, et al. Development of the 25-item National Eye Institute Visual Function Questionnaire. Arch Ophthalmol 2001;119:1050–1058.
Original study reprint requests: Carol M. Mangione, Division of General Internal Medicine and Health Services Research, Department of Medicine, UCLA, 911 Broxton Plaza, Box 951736, Los Angeles, CA 90095–1736.
To develop and test the psychometric properties of a 25-item version of the National Eye Institute Visual Function Questionnaire (NEI VFQ-25).
A prospective observational cohort study.
Eleven university-based ophthalmology practices and the National Eye Institute Clinical Center, Bethesda, MD.
Supported by the NEI, Bethesda, MD, and The Research Division of Merck Pharmaceuticals, Whitehouse Station, NJ.
Inclusion criteria: Participants had to have one of the following eye conditions: age-related cataracts, age-related macular degeneration, diabetic retinopathy, primary open angle-glaucoma, cytomegalovirus retinitis, or low vision from any cause.
Samples of visually impaired persons who completed the 51-item NEI VFQ pilot test in 1994 and the NEI VFQ Psychomotor Field test in 1996 were used for analysis. Seven of the 12 sites also enrolled persons in a reference sample. Reference sample participants had no evidence of underlying eye disease but were scheduled for either screening eye examinations or correction of refractive error.
Internal consistency estimates for the NEI-VFQ-25 subscales ranged from 0.71 to 0.85. Among persons with eye diseases, all of the eight multiitem subscales had internal consistency estimates greater than or equal to 0.70, indicating acceptable reliability for group-level comparisons. Correlations between the NEI VFQ-25 version of each subscale and their respective long-form version were greater than 0.90. Correlations between responses on the NEI-VFQ-25 and ETDRS visual acuity were within the range of 0.65 to 0.70 for subscales that reflected degree of difficulty with visual activities. The subscales of ocular pain showed a correlation ranging from 0.06 to 0.11.
The reliability and validity of the NEI VFQ-25 are comparable to those of the 51-item NEI VFQ field test version of the survey. This shorter version will be more feasible in settings such as clinical trials where interview length is a critical consideration. In addition, preliminary analyses indicate that the psychometric properties of the NEI VFQ-25 are robust for the eye conditions studied; this suggests that the measure will provide reproducible and valid data when used across multiple conditions of varying severity.
The authors are to be congratulated on the well-designed and thoughtful development of a shorter vision-targeted, health-related quality-of-life questionnaire that encompasses more than 85% of the variance seen in the longer questionnaire (NEI VFQ-51). Because the shorter questionnaire takes a subject only 5 minutes to complete whereas the longer version takes 15 minutes, the shorter questionnaire is less of a burden on a participant in a study. Thus, the development of a shorter questionnaire by the authors is a tremendous contribution. Because the authors removed questions with ceiling effects, the mean subscale scores for the NEI VFQ-25 were significantly lower than scores for the same 51-item subscales. Thus, the NEI VFQ-25 may be more responsive than the NEI VFQ-51 to subjects with early ocular disease. An important point that the authors made is that the three-item driving scale in the NEI VFQ-25 described in this article should be used instead of the two-item driving scale that was present in the prepublication version.
In summary, this is an excellent manuscript that should make investigators comfortable with using the NEI VFQ-25 instead of the NEI VFQ-51.