Patient-Reported Outcomes in RLBP1 Retinal Dystrophy: Longitudinal Assessment in a Prospective Natural History Study

To evaluate the performance of two non-disease-specific patient-reported outcome (PRO) instruments, the National Eye Institute Visual Function Questionnaire-25 (VFQ-25) and the Low Luminance Questionnaire (LLQ), in patients with retinaldehyde-binding protein 1 retinal dystrophy (RLBP1 RD). PROs were assessed using the VFQ-25 and LLQ. Rasch analysis was conducted to estimate person and item measures of the VFQ-25 and LLQ questionnaires to determine the association between the two PROs. In addition, the association between these two instruments and their correlations to weighted measures of visual function and disease progression were analyzed in this three-year PRO-focused sub-study of a five-year prospective natural history study. Forty-two patients participated, with most of them having completed at least two PRO follow-up visits at least one year apart. The mean VFQ-25 scores were lowest for distance activities (39.2-49.0) and peripheral vision (37.5-52.4), with mean LLQ subscale scores generally low (