Validation of a French Version of the Visual Function and Corneal Health Status Instrument and Correlation With Vision and Glare Measurements in Fuchs Endothelial Corneal Dystrophy.

Abstract

To validate a French version of the Visual Function and Corneal Health Status (V-FUCHS) instrument in Fuchs endothelial corneal dystrophy (FECD) and to correlate questionnaire scores with objective measurements of best-corrected visual acuity (BCVA) and intraocular straylight. The original V-FUCHS 15-item instrument was designed to assess VA and glare in patients with FECD. It was translated from English to French and back translated to English by independent translators. The questionnaire was administered on 2 occasions (4 weeks apart), and BCVA, modified Krachmer grade, and straylight were measured. Construct validity, internal consistency, test-retest reliability, and predictive validity were assessed. A total of 159 subjects, aged 41 to 86 years, were prospectively recruited from July 2019 to October 2020 and classified into 6 groups: mild, moderate, or advanced FECD; unilateral or bilateral Descemet membrane endothelial keratoplasty for FECD; and healthy controls (n = 35). Construct validity was confirmed by item response theory model. Cronbach alpha demonstrated excellent internal consistency (VA: 0.91, glare: 0.88), and intraclass correlations showed good test-retest reliability (VA: 0.75 and glare: 0.82). Significant correlations were observed between both VA and glare factors and the modified Krachmer grade, BCVA, and straylight. The proposed French version of the V-FUCHS instrument provides a valid and reliable tool for the assessment of visual disability in patients with FECD. This questionnaire bridges the gap between self-reported FECD symptoms and objective clinical measurements, which may prove useful to optimize the timing of surgery and to assess postoperative improvement in symptoms.