Although CNTF and PEDF have been shown to rescue photoreceptor morphologies and prolong photoreceptor survival in rodent models of retinal degeneration, they may suppress retinal function, as determined by ERG recoding (Liang et al., 2001; Miyazaki et al., 2003; Buch et al., 2006). This evidence concerns the gene CNTF and retinal degeneration.