The dissected retinas were dissociated in EBSS containing papain and DNase (Worthington) for 20min at 37℃, with gentle shaking every 5min, then digestion was stopped by adding Ovomucoid/EBSS (Worthington). The dissociated retinal cells were incubated with FC block antibody (1:100, BD Biosciences 553141), and then stained with Thy1.2-PE antibody (1:100, Invitrogen 12-0902-82) and DAPI. FACS sorting was performed with a BD FACSAria IIIu instrument. ATAC-seq libraries were prepared from the purified RGCs using TruePrep DNA Library Prep Kit V2 for Illumina.