Improved Rod Sensitivity as Assessed by Two-Color Dark-Adapted Perimetry in Patients With RPE65-Related Retinopathy Treated With Voretigene Neparvovec-rzyl.

Purpose: The purpose of this study was to evaluate rod-mediated function with two-color dark-adapted perimetry (2cDAP) in patients with RPE65-related retinopathy treated with voretigene neparvovec-rzyl.

Methods: Following dilation and dark adaptation, 2cDAP and FST were performed. The 2cDAP was measured on an Octopus 900 perimeter (Haag-Streit) with cyan (500 nm wavelength) and red (650 nm wavelength) stimuli. Hill of vision (HOV) analysis was performed on 2cDAP perimetry with Visual Field Modeling and Analysis (VFMA). Full field threshold stimulus testing (FST) was also measured as a secondary measure of rod-mediated function, and assessed on a Diagnosys Espion with the ColorDome stimulator (Diagnosys LLC).

Results: Eight eyes from 4 patients who were treated with voretigene bilaterally had rod function assessed by 2cDAP testing at least 1 year after treatment. There was statistically significant improvement in 2cDAP following gene augmentation therapy. HOV VFMA analysis showed widespread improvements that extended beyond the treatment bleb and statistically significant improvement in HOV analysis volumetric measurements post-treatment to cyan and red stimuli. FST testing performed in six eyes from three patients demonstrated statistically significant improvement to all chromatic stimuli following treatment.

Conclusions: These findings demonstrated statistically significant improvement in 2cDAP and FST following treatment with voretigene.

Translational Relevance: These findings provide a sensitive method of assessing rod-mediated function in a topographic manner that may be useful in future clinical trials for inherited retinal dystrophies.