Effect of RPE65 inhibitors on mouse cone dark adaptation in vivo. The recovery of cone b-wave flash sensitivity after a 90% bleach was compared between Gnat1^−/− mice treated with DMSO (n = 16) and mice treated with RPE65 inhibitors. (A–C) The late, RPE visual cycle–driven phase of cone dark adaptation was suppressed by emixustat (A; n = 14) and by MB-001 (B; n = 14), but not by QEA-B-001-NH₂ (C; n = 10). The early, retina visual cycle–driven phase of cone dark adaptation was unaffected in all three cases. Data are presented as means ± SEM.