NDP and Norrie disease: In contrast, Ndp-/Y choroidal vessel volume was not significantly different from wildtype (19.8 ± 1.53 × 106μm3 and 19.2 ± 0.387 × 106μm3, respectively; p = 0.9930; Figures 5B and 5C), indicating that the Norrie disease phenotype is specific to retinal and not choroidal vasculature.