(A) Schematic showing the timeline of the OIR protocol. Pups were placed in 75% oxygen (hyperoxia) from P7 to P10, then placed back under normal oxygen conditions (normoxia) until P15. Tamoxifen was injected at P10–P12 and P14. (B and C) Representative images of the retinal vasculature stained with IsoB4 in Casp-8WT and Casp-8ECKO mice. Red space indicates the avascular area (B), and red outlines indicate neovascular tufts (C). (D and E) Pathological neovascularization is reduced in Casp-8ECKO mice (D) compared with Casp-8WT littermates, while the avascular area was higher in Casp-8ECKO mice (n = 16 WT, n = 8 ECKO). (F and G) Retroorbital injection of IsoB4–Alexa Fluor 647 did not reveal any difference in vessel perfusion among Casp-8ECKO and Casp-8WT mice (n = 11 WT, n = 10 ECKO), as quantified by measuring Alexa Fluor 647 fluorescent intensity in IsoB4–Alexa Fluor 568–labeled vessels. Data are shown as mean ± SEM from 3 independent litters. *P <0.05; ***P < 0.001, 2-tailed unpaired Student’s t test. Scale bars: 500 μm (B); 250 μm (C); 100 μm (F).