BACKGROUND: This retrospective real-world study evaluated the effectiveness and safety of subretinal voretigene neparvovec (VN) in French patients (six children, six adults) with inherited retinal dystrophies. METHODS: Data were collected from medical records for the year following bilateral treatment with subretinal VN. Functional vision was assessed using the Streetlab mobility course with obstacles. The main outcome was Percentage of Preferred Walking Speed (PPWS) 1 month after treatment (the average speed to navigate the obstacle course as a percentage of the speed to walk straight for 4 m without obstacles at 500 lux). RESULTS: PPWS median relative improvement to month 1 was 63.9% (interquartile range 47.8%
88.5%) at 2 lux. Gains were sustained to month 6, were comparable in children and adults, with similar patterns at 7.5 and 50 lux. Course completion time and the number of collisions improved at month 1 at 2 lux. Median full-field stimulus test (FST) improved at month 1 (-33.2 [interquartile range -33.7
-19.8] dB), with improvements sustained to month 24. Over the study, best corrected visual acuity (BCVA) appeared stable, and kinetic visual field had no discernible pattern. All patients experienced at least one ocular AE related to surgery, VN, or both. One serious AE occurred (retinal detachment in a child), and was considered related to surgery. Chorioretinal atrophies occurred in four adults and one child, with no impact on FST. CONCLUSIONS: Functional vision, measured in the Streetlab mobility course, demonstrated rapid, sustainable improvements in lower light intensities. Safety data were in line with current knowledge for VN.