Association Between Quality of Life and Visual Function in Inherited Retinal Disease: A Cross-sectional Study in a Retinal Genetics Centre

BACKGROUND: Inherited retinal diseases account for the leading cause of blindness amongst working-age adults in the United Kingdom. The approval of novel therapies for these diseases requires an understanding of how clinical measures of retinal function relate to self-perceived visual disability. This study investigates the association between visual function and quality-of-life in patients with inherited retinal disease, to identify meaningful health outcomes. METHODS: A cross-sectional study (ISRCTN24016133) was conducted in patients with monogenic retinal disease. Vision-related and health-related quality-of-life were assessed using psychometrically validated questionnaires: Visual Function Questionnaire-25 (VFQ-25), Low Luminance Questionnaire (LLQ) and EuroQoL-5D-5L. Visual function measures included best-corrected visual acuity (VA) in ETDRS and Moorfields acuity chart (MAC) letters, low luminance VA (LLVA) and mesopic microperimetry. RESULTS: Twenty-five patients were recruited. The median age was 30 years (interquartile range 23-48) and 80% of patients were male. LLQ scores were lower than VFQ-25 findings and exhibited fewer ceiling and floor effects. Microperimetry was the only significant predictor of VFQ-25 and LLQ scores (p = 0.04, R² = 37% and p = 0.01, R² = 54%, respectively). No significant associations were observed between other visual function measures and questionnaire scores. A linear mixed model found no significant difference in the predictive value of the better compared to the worse eye for questionnaire scores (β = 2.14, SE = 4.88, p = 0.35). There was no significant correlation between EQ-VAS scores and VFQ-25 or LLQ findings (ρ ≈ 0, p > 0.90). CONCLUSIONS: Microperimetry is a patient-relevant measure in inherited retinal diseases. This study demonstrates to stakeholders, such as regulatory bodies, how visual function measures translate to patients' quality-of-life. CLINICAL TRIAL NUMBER AND REGISTRATION DATE: ISRCTN24016133 ( http://www.isrctn.org/) , 17 August 2022.