BEST1 and retinal degeneration: Our mouse model (Sod2flox/flox/PVMD2-rtTA; tetO-PhCMVcre) involves RPE-specific deletion of Sod2, using the cre-lox system, and results in a gradual retinal degeneration demonstrated by reduction in electroretinogram (ERG) amplitudes and in the thickness of the ONL that are statistically significant by 6 months of age.10 In this study, we examined whether Sod2 gene therapy could restore visual function and retinal degeneration in the Sod2flox/flox/VMD2-cre mice.