Quality of life in patients with CRB1-associated retinal dystrophies: A longitudinal study

Purpose: To assess the longitudinal vision-related quality of life among patients with CRB1-associated inherited retinal dystrophies. Methods: A longitudinal questionnaire study included 22 patients with pathogenic CRB1 variants. The National Eye Institute Visual Function Questionnaire (39 items, NEI VFQ-39) was applied at baseline, two-year follow-up, and 4-year follow-up. Classical test theory was performed to obtain subdomain scores and in particular 'near activities' and 'total composite' scores. The Rasch analysis based on previous calibrations of the NEI VFQ-25 was applied to create visual functioning and socio-emotional subscales. Results: In total, 22 patients with pathogenic CRB1 variants were included, with a median age of 25.0 years (IQR: 13-31 years) at baseline and mean followup of 4.0 +/- 0.3 years. A significant decline at 4 years was observed for 'near activities' (51.0 +/- 23.8 vs 35.4 +/- 14.7, p = 0.004) and 'total composite' (63.0 +/- 13.1 vs 52.0 +/- 12.1, p = 0.001) subdomain scores. For the Rasch-scaled scores, the 'visual functioning' scale significantly decreased after 4 years (- 0.89 logits; p = 0.012), but not at 4-year follow-up (+0.01 logits; p = 0.975). The 'socio- emotional' scale also showed a significant decline after 2 years (-0.78 logits, p = 0.033) and 4 years (- 0.83 logits, p = 0.021). Conclusion: In the absence of an intervention, a decline in vision-related quality of life is present in patients with pathogenic CRB1 variants at 4-year follow-up. Patient-reported outcome measures should be included in future clinical trials, as they can be a potential indicator of disease progression and treatment efficacy.