Vision-Related Quality of Life in Keratoconus: Cross-Sectional Evaluation and Changes After Corneal Cross-Linking

Purpose To evaluate vision-related quality of life (VR-QoL) in keratoconus using the Portuguese-validated Keratoconus Outcomes Research Questionnaire (KORQ), explore its association with clinical and tomographic parameters, and assess short-term changes following corneal collagen cross-linking (CXL). Design Single-center observational study comprising a cross-sectional analysis and a prospective cohort. Subjects 153 keratoconus patients were enrolled in the cross-sectional analysis, including 25 compared with 25 age-matched healthy controls. The prospective cohort included 32 patients (17 undergoing CXL, 15 untreated). Methods KORQ subscale scores were examined for associations with visual acuity, keratometric parameters, and tomographic staging. Prospective participants completed the KORQ at baseline and 6 months, with longitudinal changes analyzed using a two-way mixed analysis of variance. Results Keratoconus patients reported significantly worse VR-QoL than controls on both subscales (Activity Limitation: p=0.046, r=0.33; Symptoms: p=0.013, r=0.41). Activity Limitation scores showed modest but significant associations with keratometric severity, most notably with Kmax (ρ=−0.278, p=.001), while Symptoms were independent of clinical parameters. CXL was associated with short-term clinical improvement and keratometric stabilization. A significant Time×Treatment interaction was observed for the Symptoms subscale in unadjusted (p=0.004) and adjusted analyses (p=0.022), indicating a differential evolution of symptoms between groups. Conclusions Keratoconus is associated with a substantial reduction in VR-QoL that only partly correlates with standard clinical and tomographic measures. A differential evolution of symptom perception was observed between treated and untreated patients, persisting after adjustment for key baseline covariates. These results support the use of the KORQ as a complementary outcome measure in keratoconus research and clinical practice.