Loss-of-function mutations in Norrin (Ndpy/−) or Fzd4 (Fzd4−/−) mouse model also leads to similar ocular vascular defects, such as lack of two intraretinal capillary beds with enlarged, tortuous superficial vessels, failed regression of hyaloid vasculature, fenestrations in several vitreal face vessels, and retinal hemorrhage [134,140]. This evidence concerns the gene FZD4 and Retinal hemorrhage.