[The German version of the Visual Function and Corneal Health Status (V‑FUCHS): a Fuchs dystrophy-specific visual disability instrument].

Background: In Fuchs' endothelial corneal dystrophy (FECD), the timing and expectation of interventions has changed in recent years because of improved therapeutic options. To assess outcomes and compare interventions, a patient-reported quantification of visual disability is important.

Objective: To develop the German version of the Visual Function and Corneal Health Status (V‑FUCHS), an instrument specifically for patients with FECD, and to assess its retest reliability and validity.

Material And Methods: The V‑FUCHS was translated to German by certified forward and backward translators. Patients tested the translated questions regarding content areas, language and problem questions. After the pretest, V‑FUCHS was assessed for retest reliability and validity in FECD patients. Patients were also asked to complete a cataract-specific questionnaire (Catquest-9SF) and to complete V‑FUCHS again after 6 weeks to assess retest reliability.

Results: After successful pretesting in 30 patients, V‑FUCHS was completed by another 52 FECD patients before endothelial keratoplasty. Participants (median age 69 years) were (self-)employed or homemakers (42%), 49% were active vehicle drivers. The retest reliability confirmed agreement and consistency of response (intraclass correlation coefficient, > 0.60, both factors). The V‑FUCHS Visual Acuity score correlated with the Catquest-9SF score (r = 0.77; 95% CI, 0.67-0.85), whereas correlation of the Glare Factor specific for Fuchs' endothelial dystrophy with Catquest-9SF was weaker (r = 0.65; 95% CI, 0.50-0.76).

Conclusion: V‑FUCHS allows for standardized quantification of visual disability in patients with FECD. The German version of V‑FUCHS is a valid and reliable visual disability instrument. It may serve as a patient-reported outcome measure and needs to be studied further in clinical practice, research and trials.