Retinal layer thickness in wild-type, Gli3+/-, Pax6+/- and Pax6+/-; Gli3+/- eyes. (A) Schematic representation of areas of retinal layer measurements in wild-type and mutant eyes. Measurement of retinal layers for (B) whole retinal thickness, (C) outer nuclear layer (ONL), (D) inner nuclear layer (INL), (E) outer plexiform layer (OPL), (F) inner plexiform layer (IPL) showing average thickness (μm) (+/- s.e.m.) for each genotype group. Significant differences between genotypes are shown with brackets. l, lens; r, retina; on, optic nerve. * P = < 0.05; ** P = 0.001.