Das neuroophthalmologische Supplement des NEI-VFQ: Teststatistische Überprüfung und Validierung an einer Stichprobe prä- und postchiasmatisch geschädigter Patienten

Abstract

The National Eye Institute Visual Function Questionnaire (NEI-VFQ) is not sufficient to assess vision-related quality of life in patients with vision impairments caused by neuroophthalmic deficits. The neuroophthalmic supplement to the NEI-VFQ is currently only available in an English version. The supplement was translated into German and three items concerning visual field loss were added. NEI-VFQ and supplement data were collected from 62 pre- and postchiasmatic patients with visual field defects and from 245 healthy reference persons. NEI-VFQ and supplement were psychometrically tested and validated. Relations between visual field variables and vision-related quality of life were assessed. The patient group showed diminished quality of life in 10 NEI-VFQ subscales and in eight supplement items when compared to age-matched healthy controls. Correlations between supplement and visual field diagnostic variables demonstrate moderate relations between visual field loss and deterioration of vision-related quality of life. A Cronbach's α of 0.81 for the supplement can be increased to 0.92 in combination with the NEI-VFQ, the sole application of the NEI-VFQ generates an alpha of 0.93 in this sample. A factor analysis reveals four factors that cover the 13 items capturing the following issues: 'severity/problems due to the visual field defect", "unusual eyelid appearances", "blurry vision/double vision" and "diverse vision of both eyes"; 72% of the variance can be explained by these four factors. The German translation of the neuroophthalmic supplement to the NEI-VFQ captures additional vision-specific problems beyond the sole NEI-VFQ that are often reported by patients with vision impairments after brain damage. Although the relevance of some items can be questioned, nevertheless the supplement qualifies for an enhanced outline of subjective vision impairments that are not included in the previous NEI-VFQ.