Cross-validation of the Turkish version of the 25-item National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25)

PURPOSE: To test the validity and reliability of the Turkish version of the self-administered form of the National Eye Institute Visual Functioning Questionnaire (NEI-VFQ 25).

METHODS: Patients with no limitations to respond to a health status interview and affected by a chronic eye disease were enrolled. The Turkish versions of the abbreviated form of World Health Organization Quality of Life (WHOQOL-BREF) and the NEI-VFQ 25 instruments were administered to all participants.

RESULTS: The mean (SD) age of the participants was 60.9 (14.5) years. There were 61 patients with one of the following conditions: Cataract (57.4%), diabetic retinopathy (13.2%), age related macular degeneration (ARMD) (11.4%), glaucoma (9.8%) and degenerative myopia (8.2%). The Cronbach alpha of the overall scale was 0.97; the Cronbach alpha ranged from 0.94 to 0.78 for the subscales. The physical, psychological, environmental and social domains of the WHOQOL-BREF had fair to good correlations with the NEI-VFQ 25 (r = 0.68 to r = 0.26), which indicated a sufficient convergent validity. Patients with lower visual acuity (VA) had lower index scores than those with higher VA (p = 0.001), which showed a sufficient responsiveness.

CONCLUSION: Statistical analysis showed that Turkish version of the NEI-VFQ is a valid and reliable instrument to measure vision-related quality of life in patients with chronic eye diseases.