To analyze the progression and extent of retinal degeneration in Ppt1 ko mice, we first determined the thickness of the entire retina, the inner retina (i.e. from outer plexiform layer to vitreal retina margin) and the inner nuclear layer in 45-, 112- and 240-day-old mutant and wild-type retinas (Fig. 7). Here, PPT1 is linked to retinal degeneration.