Vision-Related Quality of Life in Keratoconus: A Save Sight Keratoconus Registry Study
Purpose: To assess vision-related quality of life using the Impact of Vision Impairment Questionnaire (IVI) in patients with keratoconus enrolled in the Save Sight Keratoconus Registry.
Methods: In this cross-sectional study, data on 107 keratoconic patients were collected through a prospectively designed web-based registry from a quaternary referral eye hospital and 2 corneal subspecialty practices. Vision-related quality of life was evaluated using the IVI. Rasch analysis was used to transform the IVI responses into interval-level measures comprising reading, mobility, and emotional well-being subscales. Associations between best-corrected visual acuity (BCVA), maximum simulated keratometry (Kmax), steep keratometry (K2), and pachymetry for each eye and IVI subscale scores were evaluated with univariate (Pearson correlations) and multivariable regression adjusted for age and gender.
Results: Of the 107 patients, 37 (34.5%), 41 (38.0%) and 29 (26.9%) had mild, moderate, and severe keratoconus, respectively. On uni- and multivariable analysis, BCVA in the better eye had the strongest association with reading [r = 0.51; 95% confidence interval (CI), 0.35-0.64, P = 0.004] and mobility (r = 0.55; 95% CI, 0.41-0.67, P < 0.001) subscale scores. BCVA in the better and worse eye, both had the joint strongest associations with emotional scores on univariate analysis, but only the latter was significant on multivariable analysis (r = 0.37; 95% CI, 0.20-0.53, P < 0.001). K2 and Kmax in the better eye also displayed significant associations with reading and mobility scores. Conclusions: In patients with keratoconus, BCVA in the better eye had the strongest correlation with reading and mobility scores, whereas BCVA in the worse eye was significantly correlated with emotional scores.