Performance and repeatability of the NEI-VFQ-25 in patients with dry eye

The use of the National Eye Institute Visual Function Questionnaire (NEI-VFQ) has increased as a method of assessing patients' impressions of their vision-specific quality of life. The purpose of this study was to assess the performance and test-retest repeatability of the 25-question format of the NEI-VFQ in patients with dry eye.

The self-administered NEI-VFQ-25 was administered to 75 patients with dry eye on two occasions in a university-based optometry practice. Dry eye severity was assessed with use of the European criteria for dry eye. The weighted kappa statistic (kappa(w)) was used to evaluate test-retest repeatability of the NEI-VFQ-25 individual test questions, and the 95% limits of agreement and the intraclass correlation coefficients were calculated for the overall VFQ and subscale scores.

With use of the European dry eye criteria, 21.9% of participants were classified with moderate to severe dry eye. For the sample, the ocular pain subscale score was lower (indicating more ocular pain) than published normative values. Repeatability of individual NEI-VFQ-25 questions ranged from moderate to substantial (kappa(w) values: 0.42 [pain and discomfort] to 0.90 [stay home because of vision]). The intervisit mean (+/- standard deviation) difference in the overall VFQ score was -0.66 +/- 4.26 (95% limits of agreement: -9.02, 7.69), and the intraclass correlation coefficient for the ocular pain subscale was 0.57.

Patients with dry eye have lower ocular pain subscale scores. The repeatability of the overall NEI-VFQ score and the subscale scores was moderate to high, and it may be influenced by the number of questions in each subscale.